Your gstreamer register seems to be corrupted somehow. Try to remove 
~/.gstreamer* and to run gst-register-0.8 as root.

I removed the directory:
~/.gstreamer-0.8/
for both my own account and the root account. Then when I run
gst-register-0.8
as root I get:


(process:23177): GLib-GObject-WARNING **: type name `rner-tl">&nbsp;</div>
                        <div id="rhlp-content">

<div class="article" lang="en"><div class="titlepage"><div><div><h1
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element %s' contains invalid characters

(process:23177): GLib-GObject-CRITICAL **: file gtype.c: line 2254
(g_type_register_static): assertion `parent_type > 0' failed

(process:23177): GStreamer-CRITICAL **: file gstelementfactory.c: line 199
(gst_element_register): assertion `g_type_is_a (type, GST_TYPE_ELEMENT)' failed

GStreamer-ERROR **: file gst.c: line 516 (gst_register_core_elements): assertion
failed: (gst_element_register (plugin, "bin", GST_RANK_PRIMARY, GST_TYPE_BIN))
aborting...
Aborted

Looks like a gstreamer bug, reassigning

Upgrading to gstreamer 0.8.7 appears to have fixed this problem.

Thanks for your help