In work I reset Firefox back to the basic state because it suggested to do so, with it being slow to come in. Not long afterwards I got a warning from this site too. Didn't note details, something about a frame. Assumed it was the weak link advert causing the issue. If ad providers can't avoid that issue then they ought to go out of business as site owners switch to those who can.
I kept getting those warnings Mrs O, despite running numerous Malware scans. In the end I got rid of Firefox then loaded it up on my system again .... and the threats went! Must have got a virus in FF.