Unable to play mp3s in wmp 11 on vista, however they play ..

I am running a clean install of Vista (Home premium OEM) and am unable
to play any of my mp3's in windows media player 11 or windows media
center. Whenever I try to play an mp3 I get the following error
"Windows Media Player cannot access the file. The file might be in
use, you might not have access to the computer where the file is
stored, or your proxy settings might not be correct." The files are
all stored in [username]\music, I dont think permissions are a problem
as winamp will play the same files fine. I have tried deleting and
recreating the library and it still doesnt work. I have also tried
riping a CD to mp3. WMP will create the mp3s fine, but when I try to
play them it gives me the same error. Any suggestions?