Seems like adware to me, even if you have ad-aware. Remember that no protection program will provide 100% protection. Sometimes, things can slip pass it. Might I suggest temporarily trying another scan just to be make sure?
Oh but before you do that, go to Tools→Options→Content→Click the "Exceptions" button next to "Block popups". Delete anything there you don't know.
Oh but before you do that, go to Tools→Options→Content→Click the "Exceptions" button next to "Block popups". Delete anything there you don't know.