I think is adbrite because they are the one thats serving doubleclicks ads and stuff like that. It shows the spyware after i scan my PC. It was advertising,doubleclick,ehg-hollywoodmedia.hitbox,and mediaplex. Those are spywares which i saw serving through adbrite earlier. They need to fix this as soon as possible
have you checked your site logs? which site is sending pop up? if you are using adsense on this web site which are getting pop up, it's not allowed getting traffic from pop up