Need Help...Gumblar Virus on Forum

[BAWSNIAN]

Hey guys...I need some help please...I have this so called Gumblar Virus on my Forum...A couple of people that wanted to register have run into it on registration..

Here is a Picture of it...

https://vborg.vbsupport.ru/external/2009/05/85.jpg

Forum responding very slowly at the moment and i have turned it off for the time being..

Anybody know how i can remove this from my Forum...Please help guys

Also im running newest vbulletin if that helps..

Thanks Guys