Wrong version of IE

So there I was, answering support calls in our helpdesk call management system when I copied a URL into the address bar of Mozilla Firefox 3.0, hit return and …

Well, I was a little surprised to read the following title bar text:

And this error message on the page.

Sorry, this application is not supported on this version of your browser. Your version of Internet Explorer needs to be upgraded to 5.5 or above.  Please contact your System Administrator.

Darn! I knew I should still be using Internet Explorer 5.5.