Ok I got it working, but in vbulletin it gives me an error. installed in its own directory on my server it works fine and doesn't throw any errors.
Warning: file_get_contents(
http://twitter.com/statuses/user_timeline/I.xml) [function.file-get-contents]: failed to open stream: HTTP request failed! HTTP/1.0 404 Not Found in [path]/TwitterClass.php on line 400
I know its relevant to the code I'm using to display the twitter feeds. But I didnt know if you could tell from the error what might be interfering.