All my lime wire mp3downloaded files are coming out in mono, not in stereo. Is it supposed to be like that?

Check your headphones if that's what you're playing thru. It might also depend on the source of your downld & quality. Those files that are 128 bps are highly possibly mono or at least joint-stereo. Instead aim for files that are 160bps or higher. I always aim for the highest bit-rate that I can. ie: 320 bps is the listeners's dream as far as mp3's go.