Well, you're not exactly giving us much to work with, are you? What's changed since the last time it worked? Have you installed, uninstalled, or upgraded anything since then? What programs are you using exactly? What outputs do you see when you run these programs from a console? Is it all mp3 files, or only some? Is it only mp3's, or do you also have problems with other types of files?
C'mon guys. Details. Learn how to ask a proper question here.