Uploading media problems

Hi there, I am new to this WPMU thing so please be kind For some reason I am having a problem uploading any media to a page or post. I have enabled music, video etc. in the admin section. When I go to upload say a pdf or a picture I get something like this:http://thisistheurl.com?getfile=54 instead of a nice neat file url I am looking for. Any ideas on what I am doing wrong?