I've been having the exact same problem. I'm using Mac OS 9.2, and the most recent Limewire free version possible (forgive me, but I do not remember the precise version number), and iTunes 2, as I recall (again, forgive me, but I'm kinda stupid when it comes to technology).

I'll download an audio MP3 file, attempt to launch, and... nothing.

I went into the HD and played around with the file path, but then I noticed that the downloaded files don't seem to be saved as the same type of MP3 file, if that makes any sense at all. My prior iTunes files have little musical note symbols next to them, and these newly downloaded files do not. Just what looks like blank white pieces of paper. Once more, I'm a luddite, so please bear with my descriptions.

If I try to launch these files from the HD, the following message appears: "The document, 'xxxxx' could not be opened, because the application that created it could not be found."

Any help would be appreciated, clearly.

-J