I had the same issue on our site. I went to cpanel-styles & templates-style manager then went to edit templates of the skin we're using and I can't remember exactly but I think it was located in the footer. I think but i'm not positive.

EDIT: Actually I think I clicked on "Search in Templates" and typed in iframe and found it that way... It was like a needle in a hay stack for me since I don't know php and all that stuff. Took me forever to find it, but I finally did. If iframe doesn't show up search for
ZUpySarUgu or something. Good luck!