Valgrind backtrace:

==19143== Invalid read of size 4
==19143==    at 0x1D4D8FEC: lookup_user_cache (smb-method.c:704)
==19143==    by 0x1D4D9E04: auth_callback (smb-method.c:757)
==19143==    by 0x1D51F145: find_server (in /usr/lib/libsmbclient.so)
==19143==    by 0x1D51F232: smbc_server (in /usr/lib/libsmbclient.so)
==19143==    by 0x1D5220B1: (within /usr/lib/libsmbclient.so)
==19143==    by 0x1D4DAB4D: do_open_directory (smb-method.c:1793)
==19143==    by 0x1B92B744: open_from_uri (gnome-vfs-directory.c:97)
==19143==    by 0x8050989: gnome_vfs_async_daemon_open_dir
(gnome-vfs-async-daemon.c:171)
==19143==    by 0x8051DD5: _ORBIT_skel_small_GNOME_VFS_AsyncDaemon_OpenDirectory
(GNOME_VFS_Daemon-common.c:128)
==19143==    by 0x1BAB78DB: ORBit_POAObject_invoke (poa.c:1141)
==19143==    by 0x1BABB802: ORBit_OAObject_invoke (orbit-adaptor.c:284)
==19143==    by 0x1BAAA541: ORBit_small_invoke_adaptor (orbit-small.c:835)
==19143==    by 0x1BAB7C4D: ORBit_POAObject_handle_request (poa.c:1350)
==19143==    by 0x1BAB8108: ORBit_POAObject_invoke_incoming_request
(poa.c:1418)==19143==    by 0x1BAA5218: giop_thread_queue_process (giop.c:781)
==19143==    by 0x1BAA52D8: giop_request_handler_thread (giop.c:490)
==19143==    by 0x1BB529C0: g_thread_pool_thread_proxy (gthreadpool.c:114)
==19143==    by 0x1BB50CC3: g_thread_create_proxy (gthread.c:561)
==19143==    by 0xDE23AD: start_thread (in /lib/tls/libpthread-2.3.4.so)
==19143==    by 0xC61B6D: clone (in /lib/tls/libc-2.3.4.so)
==19143==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==19143==
==19143== Process terminating with default action of signal 11 (SIGSEGV)
==19143==  Access not within mapped region at address 0x0
==19143==    at 0x1D4D8FEC: lookup_user_cache (smb-method.c:704)
==19143==    by 0x1D4D9E04: auth_callback (smb-method.c:757)
==19143==    by 0x1D51F145: find_server (in /usr/lib/libsmbclient.so)
==19143==    by 0x1D51F232: smbc_server (in /usr/lib/libsmbclient.so)
==19143==    by 0x1D5220B1: (within /usr/lib/libsmbclient.so)
==19143==    by 0x1D4DAB4D: do_open_directory (smb-method.c:1793)
==19143==    by 0x1B92B744: open_from_uri (gnome-vfs-directory.c:97)
==19143==    by 0x8050989: gnome_vfs_async_daemon_open_dir
(gnome-vfs-async-daemon.c:171)
==19143==    by 0x8051DD5: _ORBIT_skel_small_GNOME_VFS_AsyncDaemon_OpenDirectory
(GNOME_VFS_Daemon-common.c:128)
==19143==    by 0x1BAB78DB: ORBit_POAObject_invoke (poa.c:1141)
==19143==    by 0x1BABB802: ORBit_OAObject_invoke (orbit-adaptor.c:284)
==19143==    by 0x1BAAA541: ORBit_small_invoke_adaptor (orbit-small.c:835)
==19143==    by 0x1BAB7C4D: ORBit_POAObject_handle_request (poa.c:1350)
==19143==    by 0x1BAB8108: ORBit_POAObject_invoke_incoming_request
(poa.c:1418)==19143==    by 0x1BAA5218: giop_thread_queue_process (giop.c:781)
==19143==    by 0x1BAA52D8: giop_request_handler_thread (giop.c:490)
==19143==    by 0x1BB529C0: g_thread_pool_thread_proxy (gthreadpool.c:114)
==19143==    by 0xDE23AD: start_thread (in /lib/tls/libpthread-2.3.4.so)
==19143==    by 0xC61B6D: clone (in /lib/tls/libc-2.3.4.so)