I can also reproduce the problem, here's a backtrace:

(gdb) bt
#0  0x0011a422 in __kernel_vsyscall ()
#1  0x0014b829 in __lll_lock_wait () from /lib/tls/i686/cmov/libpthread.so.0
#2  0x00146f3b in _L_lock_752 () from /lib/tls/i686/cmov/libpthread.so.0
#3  0x00146d51 in pthread_mutex_lock () from /lib/tls/i686/cmov/libpthread.so.0
#4  0x0093a1c3 in gst_object_get_parent (object=0x9592fe0) at gstobject.c:830
#5  0x0093b7d8 in gst_object_dispatch_properties_changed (object=0x9c08060, n_pspecs=1, pspecs=0xbffbc008) at gstobject.c:527
#6  0x002e1daf in g_object_notify_dispatcher (object=0x9c08060, n_pspecs=1, pspecs=0xbffbc008) at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:326
#7  0x002e62db in g_object_notify_queue_thaw (object=0x9c08060, first_property_name=0x414a2ba "subtitle-encoding", var_args=0xbffbc0f8 "(u+\t")
    at /build/buildd/glib2.0-2.22.2/gobject/gobjectnotifyqueue.c:120
#8  IA__g_object_set_valist (object=0x9c08060, first_property_name=0x414a2ba "subtitle-encoding", var_args=0xbffbc0f8 "(u+\t")
    at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:1482
#9  0x002e6446 in IA__g_object_set (_object=0x9c08060, first_property_name=0x414a2ba "subtitle-encoding") at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:1582
#10 0x0413fcce in gst_decode_bin_set_subs_encoding (object=0x945d208, prop_id=2, value=0xbffbc238, pspec=0x999e930) at gstdecodebin2.c:865
#11 gst_decode_bin_set_property (object=0x945d208, prop_id=2, value=0xbffbc238, pspec=0x999e930) at gstdecodebin2.c:898
#12 0x002e5e85 in object_set_property (object=0x945d208, first_property_name=0x414a2ba "subtitle-encoding", var_args=0xbffbc2ac "")
    at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:968
#13 IA__g_object_set_valist (object=0x945d208, first_property_name=0x414a2ba "subtitle-encoding", var_args=0xbffbc2ac "") at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:1476
#14 0x002e6446 in IA__g_object_set (_object=0x945d208, first_property_name=0x414a2ba "subtitle-encoding") at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:1582
#15 0x0414868d in gst_uri_decode_bin_set_encoding (object=0x9598130, prop_id=5, value=0xbffbc3e8, pspec=0x9575550) at gsturidecodebin.c:491
#16 gst_uri_decode_bin_set_property (object=0x9598130, prop_id=5, value=0xbffbc3e8, pspec=0x9575550) at gsturidecodebin.c:522
#17 0x002e5e85 in object_set_property (object=0x9598130, first_property_name=0x2c183d6 "subtitle-encoding", var_args=0xbffbc45c "")
    at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:968
#18 IA__g_object_set_valist (object=0x9598130, first_property_name=0x2c183d6 "subtitle-encoding", var_args=0xbffbc45c "") at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:1476
#19 0x002e6446 in IA__g_object_set (_object=0x9598130, first_property_name=0x2c183d6 "subtitle-encoding") at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:1582
#20 0x02bfda3d in gst_play_bin_set_encoding (object=0x94700a8, prop_id=11, value=0xbffbc598, pspec=0x9448ae8) at gstplaybin2.c:1519
#21 gst_play_bin_set_property (object=0x94700a8, prop_id=11, value=0xbffbc598, pspec=0x9448ae8) at gstplaybin2.c:1574
#22 0x002e5e85 in object_set_property (object=0x94700a8, first_property_name=0x80a92aa "subtitle-encoding", var_args=0xbffbc60c "")
    at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:968
#23 IA__g_object_set_valist (object=0x94700a8, first_property_name=0x80a92aa "subtitle-encoding", var_args=0xbffbc60c "") at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:1476
#24 0x002e6446 in IA__g_object_set (_object=0x94700a8, first_property_name=0x80a92aa "subtitle-encoding") at /build/buildd/glib2.0-2.22.2/gobject/gobject.c:1582
#25 0x0808d24f in bacon_video_widget_set_subtitle_encoding (bvw=0x9466000, encoding=0x94b4570 "UTF-8") at bacon-video-widget-gst-0.10.c:3841
#26 0x0806c686 in encoding_changed_cb (client=0x9293118, cnxn_id=1761607693, entry=0x9498890, totem=0x929c800) at totem-preferences.c:489
#27 0x0017a64c in ?? () from /usr/lib/libgconf-2.so.4
#28 0x0016a630 in gconf_listeners_notify () from /usr/lib/libgconf-2.so.4
#29 0x00178484 in ?? () from /usr/lib/libgconf-2.so.4
#30 0x0017857b in ?? () from /usr/lib/libgconf-2.so.4
#31 0x0071a0f1 in g_idle_dispatch (source=0x9494cd0, callback=0xfffffe00, user_data=0x9293118) at /build/buildd/glib2.0-2.22.2/glib/gmain.c:4065
#32 0x0071be78 in g_main_dispatch (context=0x9273230) at /build/buildd/glib2.0-2.22.2/glib/gmain.c:1960
#33 IA__g_main_context_dispatch (context=0x9273230) at /build/buildd/glib2.0-2.22.2/glib/gmain.c:2513
#34 0x0071f720 in g_main_context_iterate (context=0x9273230, block=<value optimized out>, dispatch=1, self=0x915f080) at /build/buildd/glib2.0-2.22.2/glib/gmain.c:2591
#35 0x0071fb8f in IA__g_main_loop_run (loop=0x9d42c40) at /build/buildd/glib2.0-2.22.2/glib/gmain.c:2799
#36 0x02493419 in IA__gtk_main () at /build/buildd/gtk+2.0-2.18.3/gtk/gtkmain.c:1218
#37 0x08062aca in main (argc=1, argv=0xbffbca64) at totem.c:278