The original v1 jPFChat release used code to create a guest nickname if the chat user wasn't logged into joomla when entering the chat screen.   This caused more problems than it was worth.

If you're getting this... then you're still using the original v1 release.

We urge you to update your installation to the v2beta4 or v2beta6.  Our preference is that you update to v2beta6... because it uses MooTools instead of the conflicting Prototype javascript library, and... it uses MySQL as the chat cache... eliminating many other bothersome issues.