Steps to reproduce:
1. Start gnome-volume-manager
2. Close the lid
3. gnome-volume-manager crashes


Stack trace:
*** glibc detected *** gnome-power-manager: free(): invalid pointer: 0xa7f24900 ***
======= Backtrace: =========
/lib/libc.so.6[0xa6f69db0]
/lib/libc.so.6(__libc_free+0x84)[0xa6f6b3f4]
/usr/lib/libglib-2.0.so.0(g_free+0x31)[0xa7057c51]
/usr/lib/libglib-2.0.so.0(g_error_free+0x29)[0xa7042069]
gnome-power-manager[0x8055434]
/usr/lib/libgobject-2.0.so.0(g_cclosure_marshal_VOID__BOOLEAN+0x5b)[0xa711130b]
/usr/lib/libgobject-2.0.so.0(g_closure_invoke+0x13b)[0xa710414b]
/usr/lib/libgobject-2.0.so.0[0xa7114479]
/usr/lib/libgobject-2.0.so.0(g_signal_emit_valist+0x899)[0xa7115939]
/usr/lib/libgobject-2.0.so.0(g_signal_emit+0x29)[0xa7115ae9]
gnome-power-manager[0x8061549]
/usr/lib/libgobject-2.0.so.0(g_cclosure_marshal_VOID__VOID+0x4b)[0xa71113ab]
/usr/lib/libdbus-glib-1.so.2[0xa751b98a]
/usr/lib/libgobject-2.0.so.0(g_closure_invoke+0x13b)[0xa710414b]
/usr/lib/libgobject-2.0.so.0[0xa7114479]
/usr/lib/libgobject-2.0.so.0(g_signal_emit_valist+0x899)[0xa7115939]
/usr/lib/libgobject-2.0.so.0(g_signal_emit+0x29)[0xa7115ae9]
/usr/lib/libdbus-glib-1.so.2[0xa751c5f5]
/usr/lib/libdbus-1.so.2(dbus_connection_dispatch+0x25f)[0xa70d7c7f]
/usr/lib/libdbus-glib-1.so.2[0xa751449d]
/usr/lib/libglib-2.0.so.0(g_main_context_dispatch+0x181)[0xa7050851]
/usr/lib/libglib-2.0.so.0[0xa70538cf]
/usr/lib/libglib-2.0.so.0(g_main_loop_run+0x1b7)[0xa7053c87]
gnome-power-manager[0x8051cdb]
/lib/libc.so.6(__libc_start_main+0xd8)[0xa6f1c878]
gnome-power-manager[0x804dab1]
======= Memory map: ========
08048000-08073000 r-xp 00000000 03:03 2558423    /usr/bin/gnome-power-manager
08073000-08074000 rw-p 0002a000 03:03 2558423    /usr/bin/gnome-power-manager
08074000-0823b000 rw-p 08074000 00:00 0          [heap]
a6300000-a6321000 rw-p a6300000 00:00 0 
a6321000-a6400000 ---p a6321000 00:00 0 
a6464000-a646e000 r-xp 00000000 03:03 1302623    /usr/lib/gcc/i686-pc-linux-gnu/4.1.1/libgcc_s.so.1
a646e000-a646f000 rw-p 00009000 03:03 1302623    /usr/lib/gcc/i686-pc-linux-gnu/4.1.1/libgcc_s.so.1
a6482000-a64ac000 r--p 00000000 03:03 170225     /usr/local/share/fonts/Windows/verdana.ttf
a64ac000-a650c000 rw-s 00000000 00:07 4161561    /SYSV00000000 (deleted)
a650c000-a6521000 r-xp 00000000 03:03 94784      /lib/libbz2.so.1.0.3
a6521000-a6522000 rw-p 00015000 03:03 94784      /lib/libbz2.so.1.0.3
a6522000-a6553000 r-xp 00000000 03:03 1370210    /usr/lib/libcroco-0.6.so.3.0.1
a6553000-a6556000 rw-p 00030000 03:03 1370210    /usr/lib/libcroco-0.6.so.3.0.1
a6556000-a6580000 r-xp 00000000 03:03 157042     /usr/lib/libgsf-1.so.114.0.0
a6580000-a6582000 rw-p 00029000 03:03 157042     /usr/lib/libgsf-1.so.114.0.0
a6582000-a6584000 rw-p a6582000 00:00 0 
a6584000-a65b2000 r-xp 00000000 03:03 2530674    /usr/lib/librsvg-2.so.2.15.90
a65b2000-a65b3000 rw-p 0002e000 03:03 2530674    /usr/lib/librsvg-2.so.2.15.90
a65c6000-a65c7000 r-xp 00000000 03:03 2530676    /usr/lib/gtk-2.0/2.10.0/loaders/svg_loader.so
a65c7000-a65c8000 rw-p 00001000 03:03 2530676    /usr/lib/gtk-2.0/2.10.0/loaders/svg_loader.so
a65c8000-a6714000 r--p 00000000 03:03 2689275    /usr/share/icons/hicolor/icon-theme.cache
a6714000-a6ea1000 r--p 00000000 03:03 2689274    /usr/share/icons/gnome/icon-theme.cache
a6ea1000-a6eb1000 r-xp 00000000 03:03 2590902    /usr/lib/gtk-2.0/2.10.0/engines/libclearlooks.so
a6eb1000-a6eb2000 rw-p 0000f000 03:03 2590902    /usr/lib/gtk-2.0/2.10.0/engines/libclearlooks.so
a6eb2000-a6eb3000 r-xp 00000000 03:03 2243652    /usr/lib/gconv/ISO8859-1.so
a6eb3000-a6eb5000 rw-p 00001000 03:03 2243652    /usr/lib/gconv/ISO8859-1.so
a6eb5000-a6ebc000 r--s 00000000 03:03 2246221    /usr/lib/gconv/gconv-modules.cache
a6ebc000-a6ee8000 r--p 00000000 03:03 2246225    /usr/lib/locale/en_US/LC_CTYPE
a6ee8000-a6eec000 rw-p a6ee8000 00:00 0 
a6eec000-a6ef0000 r-xp 00000000 03:03 156912     /usr/lib/libXfixes.so.3.1.0
a6ef0000-a6ef1000 rw-p 00003000 03:03 156912     /usr/lib/libXfixes.so.3.1.0
a6ef1000-a6ef9000 r-xp 000000

Other information:
Here is the last message of gnome-volume-manager before it dies.

[screensaver_auth_request_cb] gpm-manager.c:2602 (23:46:51):     Failed to turn on DPMS: PQRT$D$

Feel free to ask for more information.

Gnome-volume-manager 2.15.91 on a Gentoo box.