[T2DMan]

Sorry, you have got me slightly wrong there. You definately need CSS stored as files on your vBulletin site. So change that back fast!

The xml file you have, has nothing wrong with it - its the way that you are reading it that is the issue.

The issue is to do with your browser and how it views specifically the xml files (nothing to do with vBulletin per say). When I personally look at the file you mention, I am able to view it with no problems. I get the notation at the top

This XML file does not appear to have any style information associated with it.

However, when you look at it, you get

Cannot view XML input using style sheet

How are you looking at the xml file??? - I personally use firefox, but even with explorer, I see no error. I personally am not using an xml reader, nor am I attempting to display the xml in any other format other than what it is.