MP3s? Virtually all MP3s I know of have a delay at the end which prevents them from, looping immediately. The only exceptions I've seen are Bomberman Hero songs from Galbadia Hotel.
Once I saw someone post saying to use Audacity, trim off the blank part, and convert to .OGG because of replay/loop business--OGG has no delay while MP3 does. There's my two cents.
Oh, yeah, I don't know how to work Audacity. But it's a free download, I know.
...whoops, I just saw that you--aw dang it, you already solved the prob.!