There's nothing wrong with the files. You simply have iTunes set as your default mp3 player, so any time you click on an mp3 file outside of iTunes, it will open in iTunes.

You can fix this in a couple of ways. 1) if you just want to use the default Limewire player to listen to a file (but why would you when iTunes is so much better?) then go into Limewire>>Preferences>>Player and make sure the Limewire player is clicked on.

2) Highlight an mp3 file in one of your folders, click Finder>>File>>Show Info. Then click the Open with Application tab and reassociate all your mp3 files with the mp3 player of your choice. There are any number of them on download.com or tucows if you don't like iTunes.