Showgroups coming up blank

[Cyricx]

I've had this problem with showgroups.php

http://www.guardiansoffire.com/forums/showgroups.php

It comes up blank listing noone there. I've tried uploading the original /forums/showgroups.php and /admin/usergroups.php and still had the same effect.

Any ideas on where I should look for some problems at?