A client mystically had these errors pop up where they could not open their web site with Internet Explorer. It’s strange that this error hadn’t been reported to me before because the site has been operational for a couple years now. Internet Explorer 8 doesn’t spew the error, nor does Firefox, but IE6 and IE7 would report that it couldn’t open the site with the following error window:
Thanks goes out to Richard for posting his found solution. Thanks, Richard!
Microsoft also indicates that this error can be avoided by updating your browser to the latest version, which at this time is IE8. Now, if only all my clients would do the same!