gdb log follows:

GNU gdb 6.3-debian
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This GDB was configured as "i486-linux-gnu"...Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".

(gdb) handle SIG33 pass nostop noprint
Signal        Stop	Print	Pass to program	Description
SIG33         No	No	Yes		Real-time event 33
(gdb) set pagination 0
(gdb) run
Starting program: /home/simon/gnome-nettool-1.4.1/debian/gnome-nettool/usr/bin/gnome-nettool 
[Thread debugging using libthread_db enabled]
[New Thread -1219577632 (LWP 16815)]

Program received signal SIGABRT, Aborted.
[Switching to Thread -1219577632 (LWP 16815)]
0xffffe410 in __kernel_vsyscall ()
(gdb) backtrace
#0  0xffffe410 in __kernel_vsyscall ()
#1  0xb79429d1 in raise () from /lib/tls/i686/cmov/libc.so.6
#2  0xb79442e9 in abort () from /lib/tls/i686/cmov/libc.so.6
#3  0xb797670a in __fsetlocking () from /lib/tls/i686/cmov/libc.so.6
#4  0xb797cf74 in malloc_trim () from /lib/tls/i686/cmov/libc.so.6
#5  0xb797d2ea in free () from /lib/tls/i686/cmov/libc.so.6
#6  0xb7a73054 in g_free () from /usr/lib/libglib-2.0.so.0
#7  0x0805441c in info_nic_update_stats (data=0x82157a0) at info.c:274
#8  0x080552f2 in info_nic_changed (combo=0x8127728, data=0x82157a0) at info.c:305
#9  0xb7af0ab3 in g_cclosure_marshal_VOID__VOID () from /usr/lib/libgobject-2.0.so.0
#10 0xb7ae53a8 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#11 0xb7af3b13 in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0
#12 0xb7af5150 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#13 0xb7af84f0 in g_signal_emit_by_name () from /usr/lib/libgobject-2.0.so.0
#14 0xb7c9ed06 in gtk_combo_box_get_column_span_column () from /usr/lib/libgtk-x11-2.0.so.0
#15 0xb7c9ee97 in gtk_combo_box_set_active () from /usr/lib/libgtk-x11-2.0.so.0
#16 0x08055646 in info_load_iface (info=0x82157a0) at info.c:207
#17 0x08059061 in load_info_widgets_from_xml (xml=0x80ba0f0) at main.c:617
#18 0x08059e86 in main (argc=1, argv=0xbfc159b4) at main.c:144
(gdb) thread apply all backtrace

Thread 1 (Thread -1219577632 (LWP 16815)):
#0  0xffffe410 in __kernel_vsyscall ()
#1  0xb79429d1 in raise () from /lib/tls/i686/cmov/libc.so.6
#2  0xb79442e9 in abort () from /lib/tls/i686/cmov/libc.so.6
#3  0xb797670a in __fsetlocking () from /lib/tls/i686/cmov/libc.so.6
#4  0xb797cf74 in malloc_trim () from /lib/tls/i686/cmov/libc.so.6
#5  0xb797d2ea in free () from /lib/tls/i686/cmov/libc.so.6
#6  0xb7a73054 in g_free () from /usr/lib/libglib-2.0.so.0
#7  0x0805441c in info_nic_update_stats (data=0x82157a0) at info.c:274
#8  0x080552f2 in info_nic_changed (combo=0x8127728, data=0x82157a0) at info.c:305
#9  0xb7af0ab3 in g_cclosure_marshal_VOID__VOID () from /usr/lib/libgobject-2.0.so.0
#10 0xb7ae53a8 in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#11 0xb7af3b13 in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0
#12 0xb7af5150 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#13 0xb7af84f0 in g_signal_emit_by_name () from /usr/lib/libgobject-2.0.so.0
#14 0xb7c9ed06 in gtk_combo_box_get_column_span_column () from /usr/lib/libgtk-x11-2.0.so.0
#15 0xb7c9ee97 in gtk_combo_box_set_active () from /usr/lib/libgtk-x11-2.0.so.0
#16 0x08055646 in info_load_iface (info=0x82157a0) at info.c:207
#17 0x08059061 in load_info_widgets_from_xml (xml=0x80ba0f0) at main.c:617
#18 0x08059e86 in main (argc=1, argv=0xbfc159b4) at main.c:144
(gdb)