Sorry for delay. 
I'm using locale pl_PL.

Here is info from debugger:
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1223424320 (LWP 7169)]
0xb77b5b78 in g_markup_escape_text () from /usr/lib/libglib-2.0.so.0
(gdb) thread apply all bt

Thread 2 (Thread -1230206032 (LWP 7175)):
#0  0xb7637e0a in poll () from /lib/tls/libc.so.6
#1  0xb77b46e8 in g_main_context_check () from /usr/lib/libglib-2.0.so.0
#2  0xb77b4bb8 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#3  0xb7cb770e in link_thread_io_context () from /usr/lib/libORBit-2.so.0
#4  0xb77cd472 in g_static_private_free () from /usr/lib/libglib-2.0.so.0
#5  0xb7c731ce in start_thread () from /lib/tls/libpthread.so.0
#6  0xb76418fe in clone () from /lib/tls/libc.so.6

Thread 1 (Thread -1223424320 (LWP 7169)):
#0  0xb77b5b78 in g_markup_escape_text () from /usr/lib/libglib-2.0.so.0
#1  0xb77b80b9 in g_markup_vprintf_escaped () from /usr/lib/libglib-2.0.so.0
#2  0xb77b8216 in g_markup_printf_escaped () from /usr/lib/libglib-2.0.so.0
#3  0x080a1a0b in panel_addto_make_text (name=<value optimized out>,
    desc=0x865ecd8 "Narzędzie montujące lokalne dyski i urządzenia")
    at /build/buildd/gnome-panel-2.14.1/./gnome-panel/panel-addto.c:215
#4  0x080a1c98 in panel_addto_append_item (dialog=<value optimized out>,
    model=0x84f6800, applet=0x865ec38)
    at /build/buildd/gnome-panel-2.14.1/./gnome-panel/panel-addto.c:443
#5  0x080a210e in panel_addto_present_applets (dialog=0x863f330)
    at /build/buildd/gnome-panel-2.14.1/./gnome-panel/panel-addto.c:485
#6  0x080a41a2 in panel_addto_present (item=0x8634168, panel_widget=0x8159808)
    at /build/buildd/gnome-panel-2.14.1/./gnome-panel/panel-addto.c:1497
#7  0xb7827423 in g_cclosure_marshal_VOID__VOID () from /usr/lib/libgobject-2.0.so.0
#8  0xb781b79f in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#9  0xb782a4de in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0
#10 0xb782bae9 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#11 0xb782be59 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
#12 0xb7b985ad in gtk_widget_activate () from /usr/lib/libgtk-x11-2.0.so.0
#13 0xb7ac51af in gtk_menu_shell_activate_item () from /usr/lib/libgtk-x11-2.0.so.0
#14 0xb7ac5481 in gtk_menu_shell_activate_item () from /usr/lib/libgtk-x11-2.0.so.0
#15 0xb7abbc34 in gtk_menu_reorder_child () from /usr/lib/libgtk-x11-2.0.so.0
#16 0xb7ab6540 in _gtk_marshal_BOOLEAN__BOXED () from /usr/lib/libgtk-x11-2.0.so.0
#17 0xb781b16f in g_cclosure_new_swap () from /usr/lib/libgobject-2.0.so.0
#18 0xb781b79f in g_closure_invoke () from /usr/lib/libgobject-2.0.so.0
#19 0xb782a9d8 in g_signal_stop_emission () from /usr/lib/libgobject-2.0.so.0
#20 0xb782b856 in g_signal_emit_valist () from /usr/lib/libgobject-2.0.so.0
#21 0xb782be59 in g_signal_emit () from /usr/lib/libgobject-2.0.so.0
---Type <return> to continue, or q <return> to quit---
#22 0xb7b9878f in gtk_widget_activate () from /usr/lib/libgtk-x11-2.0.so.0
#23 0xb7ab4cbd in gtk_propagate_event () from /usr/lib/libgtk-x11-2.0.so.0
#24 0xb7ab50cb in gtk_main_do_event () from /usr/lib/libgtk-x11-2.0.so.0
#25 0xb7958e1c in _gdk_events_queue () from /usr/lib/libgdk-x11-2.0.so.0
#26 0xb77b17d7 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#27 0xb77b4896 in g_main_context_check () from /usr/lib/libglib-2.0.so.0
#28 0xb77b4bb8 in g_main_loop_run () from /usr/lib/libglib-2.0.so.0
#29 0xb7ab43c6 in gtk_main () from /usr/lib/libgtk-x11-2.0.so.0
#30 0x080668bb in main (argc=-1233186808, argv=0xb67f1008)
    at /build/buildd/gnome-panel-2.14.1/./gnome-panel/main.c:92