Unfortunately, I don't have reliable repro steps for this bug it was just a bug that appeared out of the blue and then apport submitted it. For this reason, I will not reopen this bug.

Anyway, I'm fairly sure it was related to a conflict between totem and some other app with respect to pulseaudio. Check out the stacktrace that apport report for thread number one:

#0  0xb7021f98 in _int_malloc () from /lib/tls/i686/cmov/libc.so.6
#1  0xb7023cad in malloc () from /lib/tls/i686/cmov/libc.so.6
#2  0xb6fcdc65 in __gconv_open () from /lib/tls/i686/cmov/libc.so.6
#3  0xb6fcd2e0 in iconv_open () from /lib/tls/i686/cmov/libc.so.6
#4  0xb4d8a69d in iconv_simple (
    str=0x842ab28 "Assertion 'pthread_setspecific(t->key, userdata) == 0' failed at pulsecore/thread-posix.c:194, function pa_tls_set(). Aborting.", 
    to=0x5900 <Address 0x5900 out of bounds>, from=0xb7102160 "\001")
    at pulse/utf8.c:212
	new_str = 0x0
	len = <value optimized out>
	cd = <value optimized out>
	inbuf = <value optimized out>
	outbuf = <value optimized out>
	res = <value optimized out>
	inbytes = <value optimized out>
	outbytes = <value optimized out>
	__func__ = "iconv_simple"
	__PRETTY_FUNCTION__ = "iconv_simple"
#5  0xb4d9587b in pa_log_levelv_meta (level=PA_LOG_ERROR, 
    file=0xb4db6216 "pulsecore/thread-posix.c", line=194, 
    func=0xb4db62ab "pa_tls_set", 
    format=0xb4dabcfc "Assertion '%s' failed at %s:%u, function %s(). Aborting.", ap=0xb0dd31b4 "Tb۴\026b۴�") at pulsecore/log.c:161
	prefix = 0xb4db0a33 ""
	suffix = 0xb4db0a33 ""
	local_t = 0xb4da1c20 "U\211�S�����\201�\037`\001"
	text = 0x842ab28 "Assertion 'pthread_setspecific(t->key, userdata) == 0' failed at pulsecore/thread-posix.c:194, function pa_tls_set(). Aborting."
	t = 0x842ab28 "Assertion 'pthread_setspecific(t->key, userdata) == 0' failed at pulsecore/thread-posix.c:194, function pa_tls_set(). Aborting."
	n = 0x0
	location = 0x84209a0 "thread-posix.c: "
	__func__ = "pa_log_levelv_meta"
	__PRETTY_FUNCTION__ = "pa_log_levelv_meta"
#6  0xb4d95c03 in pa_log_level_meta (level=PA_LOG_ERROR, 
    file=0xb4db6216 "pulsecore/thread-posix.c", line=194, 
    func=0xb4db62ab "pa_tls_set", 
    format=0xb4dabcfc "Assertion '%s' failed at %s:%u, function %s(). Aborting.") at pulsecore/log.c:220
	ap = 0xb0dd31b4 "Tb۴\026b۴�"
#7  0xb4daa47f in pa_tls_set (t=0x816f690, userdata=0x81c0de0)
    at pulsecore/thread-posix.c:194
	r = (void *) 0x0
	__func__ = "pa_tls_set"
	__PRETTY_FUNCTION__ = "pa_tls_set"
#8  0xb4daad43 in pa_thread_self () at pulsecore/thread-posix.c:62
	t = (pa_thread *) 0x81c0de0
#9  0xb4d89ba5 in pa_threaded_mainloop_unlock (m=0xb430e8e0)
    at pulse/thread-mainloop.c:59
	__func__ = "pa_threaded_mainloop_unlock"
	__PRETTY_FUNCTION__ = "pa_threaded_mainloop_unlock"
#10 0xb55e0143 in gst_pulsesink_write (asink=0x83e2b80, data=0x8a0fd80, 
    length=0) at pulsesink.c:482
	pulsesink = (GstPulseSink *) 0x83e2b80
	sum = 880
	__FUNCTION__ = "gst_pulsesink_write"
#11 0xb7a65fdb in audioringbuffer_thread_func (buf=0x85b0808)
    at gstaudiosink.c:226
	written = 144768176
	left = 880
	len = 880
	readptr = (
    guint8 *) 0x8a0fcb0 "�%\t�@�\035�\030G\177��Zz�p�\026�\230�\016�Т<�(�\\���\200\037���b��S��P\024���,��q��H�m�h\235���1|�p\213�x�C�`*��\220v6�0\a�(f.��\006.�x\017��`�0�\200\214���\027\237�h\"2�\200S��h@\237�P�P��+o��_+��<\234� )���a��\020f\215�\030�����:"
	readseg = 13
	sink = (GstAudioSink *) 0x83e2b80
	writefunc = (WriteFunc) 0xb55dfe60 <gst_pulsesink_write>
	__FUNCTION__ = "audioringbuffer_thread_func"
#12 0xb732aa6f in g_thread_create_proxy (data=0x8947d30)
    at /build/buildd/glib2.0-2.16.3/glib/gthread.c:635
	__PRETTY_FUNCTION__ = "g_thread_create_proxy"
#13 0xb710a4fb in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#14 0xb708ce5e in clone () from /lib/tls/i686/cmov/libc.so.6