Most likely, it's a corrupt mp3 file. Go to www.versiontracker.com and get HexEdit. It's a low level hex editor that will let you look at the contents of any file regardless of its kind. Drag the Mp3 onto HexEdit's icon and open the file. You'll see several columns of numbers and letters. This is the data in the file. Scroll through the entire length of the mp3 file to examine all it's contents. It should be a constant stream of nonsense characters. If, instead, you ever see gaps filled with 0's (like thousands of zeros in a row) you have a corrupt/damaged mp3 file. Try downloading it or a different version again.

Hope this helps....