That bug has been opened on https://launchpad.net/distros/ubuntu/+source/rhythmbox/+bug/72073

"Just started up RB and it crashed after trying the stop and other features. Weird huh? I will report if it happens again.

http://librarian.launchpad.net/5086747/_usr_bin_rhythmbox.1000.crash
..."

The Ubuntu bug has a copy of the lirc config too

Debug backtrace:

 #0  rb_source_get_entry_view (source=0x0) at rb-source.c:656
 No locals.
 #1  0x08075f49 in rb_shell_player_play (player=0x82a0020, error=0x0) at rb-shell-player.c:1247
        songs = <value optimized out>
 #2  0xb50ed459 in rb_lirc_plugin_read_code (source=0x8552dd8, condition=<value optimized out>, plugin=0x8551840)
     at rb-lirc-plugin.c:128
        code = 0xb4d780f0 "0000400401008e8f 00 GREEN KONIG_IR_9836\n"
        str = 0x8557c18 "play"
        ok = <value optimized out>
        processed = <value optimized out>
        __FUNCTION__ = "rb_lirc_plugin_read_code"
 #3  0xb705dc8d in g_io_unix_dispatch (source=0x8552e30, callback=0xb50ed390 <rb_lirc_plugin_read_code>, 
     user_data=0x8551840) at giounix.c:162
        buffer_condition = 0
 #4  0xb7034802 in IA__g_main_context_dispatch (context=0x820d6d8) at gmain.c:2045
 No locals.
 #5  0xb70377df in g_main_context_iterate (context=0x820d6d8, block=1, dispatch=1, self=0x8161de8) at gmain.c:2677
        got_ownership = <value optimized out>
        max_priority = 2147483647
        timeout = 95
        some_ready = 1
        nfds = <value optimized out>
        allocated_nfds = <value optimized out>
        fds = (GPollFD *) 0xb4f31940
        __PRETTY_FUNCTION__ = "g_main_context_iterate"
 #6  0xb7037b89 in IA__g_main_loop_run (loop=0x82442b8) at gmain.c:2881
        got_ownership = -1211911200
        self = (GThread *) 0x8161de8
        __PRETTY_FUNCTION__ = "IA__g_main_loop_run"
 #7  0xb776b574 in IA__gtk_main () at gtkmain.c:1024
        tmp_list = (GList *) 0x822b3ac
        functions = (GList *) 0x0
        init = (GtkInitFunction *) 0x8298048
        loop = (GMainLoop *) 0x82442b8
...