That bug has been opened on https://launchpad.net/distros/ubuntu/+source/nautilus/+bug/66368

"during browsing inet with firefox i was notified that nautilus crashed
...
http://librarian.launchpad.net/4859549/_usr_bin_nautilus.rRzLbn.crash
crash report
...
> Thanks for your bug. Could you install libglib2.0-0-dbg and nautilus-dbg and get a new backtrace with it (you can use apport-retrace on the crash file with the coredump if you still have it or wait for the next crash once the packages are installed)
...
http://librarian.launchpad.net/4859968/_usr_bin_nautilus.1000.crash
new backtrace created with apport-retrace
...
DistroRelease: Ubuntu 6.10
ExecutablePath: /usr/bin/nautilus
Package: nautilus 2.16.1-0ubuntu2
ProcCmdline: nautilus --no-default-window --sm-client-id default2
...
 #0  IA__g_type_check_instance (type_instance=0x7369685f) at gtype.c:3209
 No locals.
 #1  0x44e71688 in IA__g_signal_handlers_disconnect_matched (
     instance=0x7369685f, mask=24, signal_id=0, detail=0, closure=0x0, 
     func=0x80c9960, data=0x8b2cb40) at gsignal.c:1928
 	n_handlers = <value optimized out>
 	__PRETTY_FUNCTION__ = "IA__g_signal_handlers_disconnect_matched"
 #2  0x080c98ce in remove_pending (startup_data=0x8b2cb40, 
     cancel_call_when_ready=0, cancel_timed_wait=1, cancel_destroy_handler=1)
     at fm-properties-window.c:4669
 No locals.
 #3  0x080cb904 in is_directory_ready_callback (file=0x83bbe68, data=0x8b2cb40)
     at fm-properties-window.c:4696
 	new_window = (FMPropertiesWindow *) 0x8d969f8
 	startup_data = (StartupData *) 0x7369685f
 #4  0x080e18b7 in ready_callback_call (directory=0x8ba5aa0, callback=0x8b89530)
     at nautilus-directory-async.c:1237
 	file_list = <value optimized out>
 #5  0x080e201b in nautilus_directory_async_state_changed (directory=0x8ba5aa0)
     at nautilus-directory-async.c:1849
 	i = 1155850724
 	file_contents = 0x83bbe68 " m!\b\006"
 	file_info = <value optimized out>
 	dot_hidden_uri = <value optimized out>
 	dot_hidden_vfs_uri = (GnomeVFSURI *) 0xbfd27c38
 	result = <value optimized out>
 	file_size = -1076724664
 #6  0x080e53c9 in nautilus_directory_call_when_ready_internal (
     directory=0x8ba5aa0, file=0x83bbe68, 
     file_attributes=NAUTILUS_FILE_ATTRIBUTE_IS_DIRECTORY, 
     wait_for_file_list=0, directory_callback=0, 
     file_callback=0x80cb1e0 <is_directory_ready_callback>, 
     callback_data=0x8b2cb40) at nautilus-directory-async.c:1319
 	callback = {file = 0x83bbe68, callback = {
     directory = 0x80cb1e0 <is_directory_ready_callback>, 
     file = 0x80cb1e0 <is_directory_ready_callback>}, 
   callback_data = 0x8b2cb40, request = {link_info = 0, deep_count = 0, 
     directory_count = 0, file_info = 1, file_list = 0, metafile = 0, 
     mime_list = 0, top_left_text = 0, large_top_left_text = 0, 
     extension_info = 0, slow_mime_type = 0}}
 	__PRETTY_FUNCTION__ = "nautilus_directory_call_when_ready_internal"
 #7  0x0812ae4b in vfs_file_call_when_ready (file=0x83bbe68, 
     file_attributes=NAUTILUS_FILE_ATTRIBUTE_IS_DIRECTORY, 
     callback=0x80cb1e0 <is_directory_ready_callback>, callback_data=0x8b2cb40)
     at nautilus-vfs-file.c:66
 No locals.
 #8  0x080f994c in nautilus_file_call_when_ready (file=0x83bbe68, 
     file_attributes=NAUTILUS_FILE_ATTRIBUTE_IS_DIRECTORY, 
     callback=0x80cb1e0 <is_directory_ready_callback>, callback_data=0x8b2cb40)
     at nautilus-file.c:5548
 	__PRETTY_FUNCTION__ = "nautilus_file_call_when_ready"
 #9  0x080c2dd6 in fm_properties_window_present (
     original_files=<value optimized out>, parent_widget=0x85fddd0)
     at fm-properties-window.c:4781
 	l = (GList *) 0x0
 	next = (GList *) 0x0
 	parent_window = <value optimized out>
 	target_files = <value optimized out>
 	pending_key = 0x85cf598 "\001"
 	__PRETTY_FUNCTION__ = "fm_properties_window_present"
 #10 0x080b197c in action_properties_callback (action=0x86450a8, 
     callback_data=0x85fddd0) at fm-directory-view.c:1445
 	selection = (GList *) 0x820fcd0
 	__PRETTY_FUNCTION__ = "action_properties_callback"
 #11 0x44e67b29 in IA__g_cclosure_marshal_VOID__VOID (closure=0x8205d48, 
     return_value=0x0, n_param_values=1, param_values=0xbfd27fcc, 
     invocation_hint=0xbfd27edc, marshal_data=0x80b1900) at gmarshal.c:77
 	data1 = (gpointer) 0x86450a8
 	data2 = (gpointer) 0x7369685f
 	__PRETTY_FUNCTION__ = "IA__g_cclosure_marshal_VOID__VOID"
 #12 0x44e5a79b in IA__g_closure_invoke (closure=0x8205d48, return_value=0x0, 
     n_param_values=1, param_values=0xbfd27fcc, invocation_hint=0xbfd27edc)
     at gclosure.c:490
 	marshal = (
     GClosureMarshal) 0x8065530 <g_cclosure_marshal_VOID__VOID@plt>
 	marshal_data = (gpointer) 0x0
 	__PRETTY_FUNCTION__ = "IA__g_closure_invoke"
 #13 0x44e6ab93 in signal_emit_unlocked_R (node=0x81ebbf8, detail=0, 
     instance=0x86450a8, emission_return=0x0, instance_and_params=0xbfd27fcc)
     at gsignal.c:2440
 	tmp = <value optimized out>
 	handler = (Handler *) 0x8cbdf40
 	accumulator = (SignalAccumulator *) 0x0
 	emission = {next = 0x0, instance = 0x86450a8, ihint = {
     signal_id = 129, detail = 0, run_type = G_SIGNAL_RUN_FIRST}, 
   state = EMISSION_RESTART, chain_type = 4}
 	class_closure = (GClosure *) 0x81ebbb0
 	handler_list = (Handler *) 0x8cbdf40
 	return_accu = (GValue *) 0x0
 	accu = {g_type = 0, data = {{v_int = 0, v_uint = 0, v_long = 0, 
       v_ulong = 0, v_int64 = 0, v_uint64 = 0, v_float = 0, v_double = 0, 
       v_pointer = 0x0}, {v_int = 0, v_uint = 0, v_long = 0, v_ulong = 0, 
       v_int64 = 0, v_uint64 = 0, v_float = 0, v_double = 0, v_pointer = 0x0}}}
 	signal_id = 129
 	max_sequential_handler_number = 39160
 	return_value_altered = 1
 #14 0x44e6c0b7 in IA__g_signal_emit_valist (instance=0x86450a8, signal_id=129, 
     detail=0, 
     var_args=0xbfd2820c "\220{EE¨Pd\b¨Pd\b8\202Ò¿¨w\026E¨Pd\b@\202±@X\202Ò¿*w\026EЦèD w\026EX\202Ò¿){æD¨Pd\bHI\227\bK¤åDЦèDøÿÿÿÿÿÿÿ¸\202Ò¿\233§åD@\202±\b")
     at gsignal.c:2199
 	_flags = <value optimized out>
 	_vtable = <value optimized out>
 	_cvalues = {{v_int = 1155530770, v_long = 1155530770, 
     v_int64 = 583060846882586642, v_double = 1.1096199615375395e-269, 
     v_pointer = 0x44e00012}, {v_int = 1157892980, v_long = 1157892980, 
     v_int64 = -4624491788680033420, v_double = -0.28913695087265201, 
     v_pointer = 0x45040b74}, {v_int = 1155551284, v_long = 1155551284, 
     v_int64 = 4990472929312526388, v_double = 4.2847811912617314e+25, 
     v_pointer = 0x44e05034}, {v_int = 1161935024, v_long = 1161935024, 
     v_int64 = 4972253794013395120, v_double = 2.5680710175596189e+24, 
     v_pointer = 0x4541b8b0}, {v_int = 140791976, v_long = 140791976, 
     v_int64 = 140791976, v_double = 6.9560478551705283e-316, 
     v_pointer = 0x86450a8}, {v_int = 0, v_long = 0, v_int64 = 0, v_double = 0, 
     v_pointer = 0x0}, {v_int = 0, v_long = 0, v_int64 = 0, v_double = 0, 
     v_pointer = 0x0}, {v_int = 0, v_long = 0, v_int64 = 0, v_double = 0, 
     v_pointer = 0x0}}
 	_lcopy_format = <value optimized out>
 	_n_values = <value optimized out>
 	return_value = {g_type = 1155908813, data = {{v_int = 142290360, 
       v_uint = 142290360, v_long = 142290360, v_ulong = 142290360, 
       v_int64 = 8817710149048, v_uint64 = 8817710149048, 
       v_float = 7.55863071e-34, v_double = 4.3565276596303144e-311, 
       v_pointer = 0x87b2db8}, {v_int = 1155971067, v_uint = 1155971067, 
       v_long = 1155971067, v_ulong = 1155971067, 
       v_int64 = 4991531621571540987, v_uint64 = 4991531621571540987, 
       v_float = 1845.74939, v_double = 5.1941909170609442e+25, 
       v_pointer = 0x44e6b7fb}}}
 	error = <value optimized out>
 	instance_and_params = (GValue *) 0xbfd27fcc
 	stack_values = {{g_type = 136224080, data = {{v_int = 140791976, 
         v_uint = 140791976, v_long = 140791976, v_ulong = 140791976, 
         v_int64 = 140791976, v_uint64 = 140791976, v_float = 6.87060652e-34, 
         v_double = 6.9560478551705283e-316, v_pointer = 0x86450a8}, {
         v_int = 0, v_uint = 0, v_long = 0, v_ulong = 0, v_int64 = 0, 
         v_uint64 = 0, v_float = 0, v_double = 0, v_pointer = 0x0}}}, {
     g_type = 0, data = {{v_int = 1159993920, v_uint = 1159993920, 
         v_long = 1159993920, v_ulong = 1159993920, 
         v_int64 = -4624493094347990464, v_uint64 = 13822250979361561152, 
         v_float = 2625.64062, v_double = -0.28906447174123073, 
         v_pointer = 0x45241a40}, {v_int = 1159164146, v_uint = 1159164146, 
         v_long = 1159164146, v_ulong = 1159164146, 
         v_int64 = 627544957042258162, v_uint64 = 627544957042258162, 
         v_float = 2423.05908, v_double = 1.041239920168897e-266, 
         v_pointer = 0x451770f2}}}, {g_type = 1087537548, data = {{v_int = 0, 
         v_uint = 0, v_long = 0, v_ulong = 0, v_int64 = 4965402001459380224, 
         v_uint64 = 4965402001459380224, v_float = 0, 
         v_double = 9.3131154467733728e+23, v_pointer = 0x0}, {v_int = 1, 
         v_uint = 1, v_long = 1, v_ulong = 1, v_int64 = 12884901889, 
         v_uint64 = 12884901889, v_float = 1.40129846e-45, 
         v_double = 6.3659873733898826e-314, v_pointer = 0x1}}}, {
     g_type = 3218243640, data = {{v_int = 1155910126, v_uint = 1155910126, 
         v_long = 1155910126, v_ulong = 1155910126, 
         v_int64 = 641585737705572846, v_uint64 = 641585737705572846, 
         v_float = 1838.3103, v_double = 9.0598388946907402e-266, 
         v_pointer = 0x44e5c9ee}, {v_int = 3, v_uint = 3, v_long = 3, 
         v_ulong = 3, v_int64 = 8589934595, v_uint64 = 8589934595, 
         v_float = 4.20389539e-45, v_double = 4.2439915834127416e-314, 
         v_pointer = 0x3}}}, {g_type = 3218243980, data = {{v_int = 149380816, 
         v_uint = 149380816, v_long = 149380816, v_ulong = 149380816, 
         v_int64 = 4611686237620100816, v_uint64 = 4611686237620100816, 
         v_float = 1.39250971e-33, v_double = 2.000097341118682, 
         v_pointer = 0x8e75ed0}, {v_int = 149380820, v_uint = 149380820, 
         v_long = 149380820, v_ulong = 149380820, 
         v_int64 = 4991531620564950740, v_uint64 = 4991531620564950740, 
         v_float = 1.39251008e-33, v_double = 5.194190052406506e+25, 
         v_pointer = 0x8e75ed4}}}, {g_type = 1, data = {{v_int = -1076723316, 
         v_uint = 3218243980, v_long = -1076723316, v_ulong = 3218243980, 
         v_int64 = -4624492679972879988, v_uint64 = 13822251393736671628, 
         v_float = -1.64457846, v_double = -0.28908747418065484, 
         v_pointer = 0xbfd2818c}, {v_int = 1159994097, v_uint = 1159994097, 
         v_long = 1159994097, v_ulong = 1159994097, 
         v_int64 = 641585720529787633, v_uint64 = 641585720529787633, 
         v_float = 2625.68384, v_double = 9.0598152392716823e-266, 
         v_pointer = 0x45241af1}}}, {g_type = 1159993920, data = {{
         v_int = -1076723316, v_uint = 3218243980, v_long = -1076723316, 
         v_ulong = 3218243980, v_int64 = 4956954615755211148, 
         v_uint64 = 4956954615755211148, v_float = -1.64457846, 
         v_double = 2.5161211188467824e+23, v_pointer = 0xbfd2818c}, {
         v_int = 0, v_uint = 0, v_long = 0, v_ulong = 0, v_int64 = 0, 
         v_uint64 = 0, v_float = 0, v_double = 0, v_pointer = 0x0}}}, {
     g_type = 1, data = {{v_int = 1156010516, v_uint = 1156010516, 
         v_long = 1156010516, v_ulong = 1156010516, 
         v_int64 = 627243519054402068, v_uint64 = 627243519054402068, 
         v_float = 1850.56494, v_double = 9.8934533547977269e-267, 
         v_pointer = 0x44e75214}, {v_int = -1076723316, v_uint = 3218243980, 
         v_long = -1076723316, v_ulong = 3218243980, 
         v_int64 = -4624492542533926516, v_uint64 = 13822251531175625100, 
         v_float = -1.64457846, v_double = -0.28909510357518609, 
         v_pointer = 0xbfd2818c}}}, {g_type = 1159729027, data = {{
         v_int = 149380816, v_uint = 149380816, v_long = 149380816, 
         v_ulong = 149380816, v_int64 = 4670938201981411024, 
         v_uint64 = 4670938201981411024, v_float = 1.39250971e-33, 
         v_double = 18950.188043444243, v_pointer = 0x8e75ed0}, {v_int = 0, 
         v_uint = 0, v_long = 0, v_ulong = 0, v_int64 = 4965402001459380224, 
         v_uint64 = 4965402001459380224, v_float = 0, 
         v_double = 9.3131154467733728e+23, v_pointer = 0x0}}}, {g_type = 1, 
     data = {{v_int = 3, v_uint = 3, v_long = 3, v_ulong = 3, 
         v_int64 = -4624492339593740285, v_uint64 = 13822251734115811331, 
         v_float = 4.20389539e-45, v_double = -0.28910636901855485, 
         v_pointer = 0x3}, {v_int = 1155910126, v_uint = 1155910126, 
         v_long = 1155910126, v_ulong = 1155910126, 
         v_int64 = 627243536234170862, v_uint64 = 627243536234170862, 
         v_float = 1838.3103, v_double = 9.8934829309295529e-267, 
         v_pointer = 0x44e5c9ee}}}, {g_type = 3, data = {{v_int = 2, 
         v_uint = 2, v_long = 2, v_ulong = 2, v_int64 = -4624491429060673534, 
         v_uint64 = 13822252644648878082, v_float = 2.80259693e-45, 
         v_double = -0.28915691375732433, v_pointer = 0x2}, {v_int = 146041512, 
         v_uint = 146041512, v_long = 146041512, v_ulong = 146041512, 
         v_int64 = 4611686237616761512, v_uint64 = 4611686237616761512, 
         v_float = 1.08584307e-33, v_double = 2.0000973396357331, 
         v_pointer = 0x8b46aa8}}}, {g_type = 146041516, data = {{
         v_int = 1162181520, v_uint = 1162181520, v_long = 1162181520, 
         v_ulong = 1162181520, v_int64 = 5457148816, v_uint64 = 5457148816, 
         v_float = 3159.72266, v_double = 2.6961897542288339e-314, 
         v_pointer = 0x45457b90}, {v_int = -1076723316, v_uint = 3218243980, 
         v_long = -1076723316, v_ulong = 3218243980, 
         v_int64 = -4624492130217066100, v_uint64 = 13822251943492485516, 
         v_float = -1.64457846, v_double = -0.28911799175877984, 
         v_pointer = 0xbfd2818c}}}, {g_type = 1159994097, data = {{v_int = 51, 
         v_uint = 51, v_long = 51, v_ulong = 51, v_int64 = 4982135949958840371, 
         v_uint64 = 4982135949958840371, v_float = 7.14662217e-44, 
         v_double = 1.2151239256234065e+25, v_pointer = 0x33}, {
         v_int = -1076723316, v_uint = 3218243980, v_long = -1076723316, 
         v_ulong = 3218243980, v_int64 = 4956954615755211148, 
         v_uint64 = 4956954615755211148, v_float = -1.64457846, 
         v_double = 2.5161211188467824e+23, v_pointer = 0xbfd2818c}}}, {
     g_type = 1166504232, data = {{v_int = 1, v_uint = 1, v_long = 1, 
         v_ulong = 1, v_int64 = -4624492133435310079, 
         v_uint64 = 13822251940274241537, v_float = 1.40129846e-45, 
         v_double = -0.28911781311035162, v_pointer = 0x1}, {
         v_int = 1166495605, v_uint = 1166495605, v_long = 1166495605, 
         v_ulong = 1166495605, v_int64 = 9756430197, v_uint64 = 9756430197, 
         v_float = 4329.93213, v_double = 4.8203169863858453e-314, 
         v_pointer = 0x45874f75}}}, {g_type = 1155850724, data = {{
         v_int = -1076723400, v_uint = 3218243896, v_long = -1076723400, 
         v_ulong = 3218243896, v_int64 = 4956954615755211064, 
         v_uint64 = 4956954615755211064, v_float = -1.64456844, 
         v_double = 2.5161211188467542e+23, v_pointer = 0xbfd28138}, {
         v_int = 1166504232, v_uint = 1166504232, v_long = 1166504232, 
         v_ulong = 1166504232, v_int64 = 5461471528, v_uint64 = 5461471528, 
         v_float = 4334.14453, v_double = 2.6983254577248996e-314, 
         v_pointer = 0x45877128}}}, {g_type = 3218243848, data = {{
         v_int = 1166495605, v_uint = 1166495605, v_long = 1166495605, 
         v_ulong = 1166495605, v_int64 = 9756430197, v_uint64 = 9756430197, 
         v_float = 4329.93213, v_double = 4.8203169863858453e-314, 
         v_pointer = 0x45874f75}, {v_int = 1155850724, v_uint = 1155850724, 
         v_long = 1155850724, v_ulong = 1155850724, 
         v_int64 = -4624491651243122204, v_uint64 = 13822252422466429412, 
         v_float = 1831.05908, v_double = -0.28914458015381528, 
         v_pointer = 0x44e4e1e4}}}}
 	free_me = (GValue *) 0x0
 	signal_return_type = 4
 	param_values = (GValue *) 0xbfd27fe0
 	node = (SignalNode *) 0x81ebbf8
 	i = 0
 	n_params = 0
 	__PRETTY_FUNCTION__ = "IA__g_signal_emit_valist"
 #15 0x44e6c279 in IA__g_signal_emit (instance=0x86450a8, signal_id=129, 
     detail=0) at gsignal.c:2243
 	var_args = 0xbfd2820c "\220{EE¨Pd\b¨Pd\b8\202Ò¿¨w\026E¨Pd\b@\202±@X\202Ò¿*w\026EЦèD w\026EX\202Ò¿){æD¨Pd\bHI\227\bK¤åDЦèDøÿÿÿÿÿÿÿ¸\202Ò¿\233§åD@\202±\b"
 #16 0x45166935 in _gtk_action_emit_activate ()
    from /usr/lib/libgtk-x11-2.0.so.0
 No symbol table info available.
 #17 0x451677a8 in gtk_action_activate () from /usr/lib/libgtk-x11-2.0.so.0
 No symbol table info available.
 #18 0x44e67b29 in IA__g_cclosure_marshal_VOID__VOID (closure=0x8b18240, 
     return_value=0x0, n_param_values=1, param_values=0xbfd2846c, 
     invocation_hint=0xbfd2837c, marshal_data=0x45167720) at gmarshal.c:77
 	data1 = (gpointer) 0x86450a8
 	data2 = (gpointer) 0x7369685f
 	__PRETTY_FUNCTION__ = "IA__g_cclosure_marshal_VOID__VOID"
...3