I disabled BBCodes for guests and post message as guest, see JavaScript error:

syntax error:
bbcodeEnabled = ;\n

The bad code is:

<div id="topicreview">

<script type="text/javascript">
// <![CDATA[
bbcodeEnabled = ;
// ]]>
</script>

Should be:

<div id="topicreview">

<script type="text/javascript">
// <![CDATA[
var bbcodeEnabled = 0;
// ]]>
</script>