IE6 Ajax error "object doesn't support this property..."

Yes, it is often that IE doesn't performe as it should! And often it is difficult to debug the error. Lately I was receiving a "object doesn't support this property or method.." error in IE6 when the Ajax open() method was called. It works just fine in Firefox and IE7 but IE6 was not saving any data. It should be noted that I am using the Prototype library which automatically retrieves the correct XMLHTTP-REQUEST object. So far so good. The relevant part was in another place. Im on a Win 2003 box and I un-installed IE7. In short, the solution was to reset the security configuration of IE6 to Medium. Somehow, the settings left from the IE7 install had triggered a setting that caused the Ajax to fail.

I hope this helps someone, spend all day on it Grrh!