I doubt that they are
all corrupt.
What exactly happens when you try to open them?
Does any kind of error message come up?
Does nothing happen?
Do they open LimeWire?
Make sure you don't try to open them from within LimeWire (the Library). Go to your Shared Folder on your Hard Drive and open them there. Then post back what happens. It may be that you just need to assign one player to playback all mp3's. Something may have been messed up in your File Exchange (Mac Control Panel).
Also, look in LimeWire (Tools menu, choose Options) Make sure that you don't have it set for LimeWire to be the default player. I think that's where that option is.
Let me know.