jPFChat v1 and v2beta1 through v2beta4 rely on the Prototype javascript library, and will NOT work in any Joomla site that also loads mootools in the template or with any module or menu.

If you are having IE6 or IE7 issues... then please upgrade your jPFChat installation to v2beta6 or v2 RC1 or later.

Also... please note:  there's been a few extensions recently added to the Joomla.org website that are jQuery based extensions (yet another javascript library).  These extensions will also cause conflicts with ANYTHING using mootools... including jPFChat.