This was placed on another closed thread, to try and keep continuity but as this has been closed, it is not being looked at. Although a similar error message was being displayed it was a different programme that caused it.
I have a friend who has had trouble with the error message as above but only when trying to access the internet. HTTP 400.
I have run after updating AVG & Spybot, both these programmes finished with no spyware or virus found.
I have cleared all temp files from IE6 and lowered to the minimum the privicy settings in IE properties, but it's still not allowing her to access the internet.