Yeah, me too - it's a javascript error - I'm on Firefox (Windows XP, not that that has any relevance).
Error: self.document.forms.threadReply is undefined
Source File: javascript: void insertTag(self.document.forms['threadReply'].message,'url',true);
Line: 1
There's still a lot of incompatibilities in Javascript from browser to browser, and without wanting to debug it, I assume this is one (and not a problem with your settings).
Edited: 27/11/2008 at 09:47