#1 Problem after install/activation

[Anonymous]

Hello,

I installed the XDForum plug-in and activated-it. When I go to back to my blog, I got an error message at the top of the page:

Warning: Invalid argument supplied for foreach() in /home/.pirouette/banffteam/banffcentre.info/blogs/leadership/test/wp-includes/functions.php on line 683

If I deactivate the plug-in, the error goes away.

Any idea where to start to fix it??

THanks!!