(gdb) bt
#0  0x40920414 in read () from /lib/libc.so.6
#1  0x401f533c in __DTOR_END__ () from /lib/libpthread.so.0
#2  0x408c7533 in _IO_file_read () from /lib/libc.so.6
#3  0x408c6e6b in _IO_file_underflow () from /lib/libc.so.6
#4  0x408c8253 in _IO_default_uflow () from /lib/libc.so.6
#5  0x408c8158 in __uflow () from /lib/libc.so.6
#6  0x408bf1a4 in _IO_getline_info () from /lib/libc.so.6
#7  0x408bf04c in _IO_getline () from /lib/libc.so.6
#8  0x408be441 in fgets () from /lib/libc.so.6
#9  0x400714d4 in g_on_error_query () from /usr/lib/libglib-1.2.so.0
#10 0x40020052 in debug_log_handler (log_domain=0x40048be0 "GStreamer", 
    log_level=6, 
    message=0xbf21f6a0 "file gstthread.c: line 357 (gst_thread_change_state): assertion failed: (!pthread_equal(self, thread->thread_id))", user_data=0x0)
    at gst.c:60
#11 0x40077a82 in g_logv () from /usr/lib/libglib-1.2.so.0
#12 0x40077b41 in g_log () from /usr/lib/libglib-1.2.so.0
#13 0x40041e4f in gst_thread_change_state (element=0x40d004b8)
    at gstthread.c:357
#14 0x4002c8bc in gst_element_set_state (element=0x40d004b8, 
    state=GST_STATE_NULL) at gstelement.c:825
#15 0x0804edfb in rb_gst_destroy () at rb-playback.c:201
#16 0x0804ea74 in rb_forward () at rb-playback.c:113
#17 0x4066c035 in gtk_marshal_NONE__NONE () from /usr/lib/libgtk-1.2.so.0
#18 0x4069b8b7 in gtk_signal_remove_emission_hook ()
   from /usr/lib/libgtk-1.2.so.0
#19 0x4069ad15 in gtk_signal_set_funcs () from /usr/lib/libgtk-1.2.so.0
#20 0x40698df3 in gtk_signal_emit () from /usr/lib/libgtk-1.2.so.0
#21 0x40ac9267 in gst_gnomevfssrc_get (pad=0x40d006b8) at gnomevfssrc.c:346
#22 0x4003d126 in gst_schedule_src_wrapper (argc=0, argv=0x40d00610)
    at gstscheduler.c:119
#23 0x4001f3fe in cothread_stub () at cothreads.c:231
#24 0x4001f768 in cothread_switch (thread=0xbf200000) at cothreads.c:360
#25 0x4003d8aa in gst_schedule_gethandler_proxy (pad=0x40d006b8)
    at gstscheduler.c:203
#26 0x40035452 in gst_pad_pull (pad=0x40d00850) at gstpad.c:1492
#27 0x40ad7cad in gst_mad_input (user_data=0x40d00788, stream=0x8352b40)
    at gstmad.c:173
#28 0x40af5fa6 in mad_decoder_finish () from /usr/lib/libmad-0.13.0b.so
#29 0x40af66cf in mad_decoder_run () from /usr/lib/libmad-0.13.0b.so
#30 0x40ad81e9 in gst_mad_loop (element=0x40d00788) at gstmad.c:338
#31 0x4003cb98 in gst_schedule_loopfunc_wrapper (argc=0, argv=0x40d00788)
    at gstscheduler.c:40
#32 0x4001f3fe in cothread_stub () at cothreads.c:231
#33 0x4001f768 in cothread_switch (thread=0xbf220000) at cothreads.c:360
#34 0x4003d8aa in gst_schedule_gethandler_proxy (pad=0x40d00910)
    at gstscheduler.c:203
#35 0x40035452 in gst_pad_pull (pad=0x40d02aa0) at gstpad.c:1492
#36 0x4003ce1d in gst_schedule_chain_wrapper (argc=0, argv=0x40d029e8)
    at gstscheduler.c:74
#37 0x4001f3fe in cothread_stub () at cothreads.c:231
#38 0x4001f768 in cothread_switch (thread=0xbf240000) at cothreads.c:360
#39 0x4003d8aa in gst_schedule_gethandler_proxy (pad=0x40d02c20)
    at gstscheduler.c:203
#40 0x40035452 in gst_pad_pull (pad=0x40d02d90) at gstpad.c:1492
#41 0x4003ce1d in gst_schedule_chain_wrapper (argc=0, argv=0x40d02cf0)
    at gstscheduler.c:74
#42 0x4001f3fe in cothread_stub () at cothreads.c:231
---Type <return> to continue, or q <return> to quit---
#43 0x4001f768 in cothread_switch (thread=0xbf260000) at cothreads.c:360
#44 0x400409e5 in gst_schedule_iterate (sched=0x40d00578)
    at gstscheduler.c:1406
#45 0x40024422 in gst_bin_iterate_func (bin=0x40d004b8) at gstbin.c:707
#46 0x4002411c in gst_bin_iterate (bin=0x40d004b8) at gstbin.c:674
#47 0x40043068 in gst_thread_main_loop (arg=0x40d004b8) at gstthread.c:584
#48 0x401e6e85 in pthread_start_thread () from /lib/libpthread.so.0
#49 0x401e6ecd in pthread_start_thread_event () from /lib/libpthread.so.0