I'm not a Limewire programmer but I would venture a guess that any file that ends in ".mp3" will be identified as an MP3 file by virtue of its name alone. So far MP3 files I've downloaded have proven to be valid and I'm currently using a G4 Mac. However I wonder what would happen if I took a file named "Anything.jpg" and renamed it "Anything.mp3" and then put it in my shared directory? Maybe your problem is with the client you're loading from?