LimeWire, being a Win-doze port, does not like the Mac conventions of File Type & Creator codes (the things that are hidden that allow files to display the correct icon and open in the correct application)

Win-doze uses file extensions, such as <dot> mp3 to identify files. No file extensions, no sharing in LimeWire Mac. Wildcards <*> are not implemented.

Download a copy of MP3RAGE and use it to rename all your files with an mp3 extension. MP3RAGE does this very quickly and in bulk by using the MP3 tags. Then you'll be able to share them.

Limewire is OK; better than Aimster which crashes all the time. Limewire never crashes, but it's still a Win-Doze port, with all that means to a Mac user.