ActiveX error after SP4 upgrade?

We’ve been through the Blaster worm fixes..service pack 4 and security updates got rid of it. Now we’re getting this error when we hit the back button on select URLs (eBay is one):

“This page provides potentially unsafe information to an ActiveX control. Your current security settings prohibit running controls in this manner. As a result, this page may not display correctly.”

Virtual Machine is enabled, browser security is set to medium. When set to low or low-medium, the error persists.

I’ve been reading all night and I get two consistent answers: (1) it’s a known bug in SP4 (and wait for the fix in the next service pack–UGH!) and (2) it’s a potential URL Hijacker. Running Spybot doesn’t help.

Does anyone know what is causing this? It’s a Win2K box. Thanks in advance.