I am having the same problem.

I'm using PHP 4.33, and XOOPS 2.0.5. I tried the patch for the update just incase, but it didn't make any difference.

I'm getting the "Fatal error: Cannot pass parameter 4 by reference in /home/evilbutsexy/www/modules/newbb/viewtopic.php on line 256" error message.

I'm baffled as I have the forums running on another site - same web host, same system, same everything.

I am somewhat of a XOOPS newbie, so any suggestions would be very much appreciated.