Modules that I am running are:
System
Forum
Contact Us
News
FAQ
Downloads
Yellow Pages
MS-Weather
Classifieds
Movie Times
FlashChat
GAMES
Google
Glossary
Friendfinder
Stockbox
VirusInfo
Job Listings
Web Stats
XoOgle

I would suggest that you deactivate the modules one by another to find the culprit.

I don't know all of them, so I would suggest this order (the unknown for me first):

Stockbox
Games
Movie Times
FlashChat
FriendFinder
Job Listings
Web Stats
Glossary
Google
Classifieds
Yellow Pages
XoOgle
MS-Weather
Downloads
News (although I hope you don't get this far)
Contact Us
Forum

Just deactivate the module, then go to the user profile, if not solved, deactivate the next module, go to user profile... clean, rinse, repeat (Have 2 windows open, so you just have to work in admin menu and then refresh the other window on the user profile)

thanks it appears the module that caused the issue was XoOgle.

OK, if you submit it to the XoOgle bug tracker I'm sure this can be fixed in later versions.

It seems to be a problem with the search function of the module, but a further investigation is necessary to find the culprit piece of code.