Re: Malware on the site?
An admin should run that URL through the database (bannerplusapi.com)...checking the post, profile, and signature/avy tables. It's likely you guys can get warnings if someone posts an image that has been hosted by that particular URL, or uses it in their signature space OR avatar.
Basically, that URL is blacklisted. It was suspended recently, according to Whois. I'm assuming Avast hasn't removed it from its blacklist yet, while it seems like Google has (among other search engines, you'll usually get the warnings from your browser because of it).