The title explains it pretty well.
I've imported a few of my own MP3s into the game and a few don't work. Yes, the music is at the right place, otherwise the playlist would not even show the tracks.
When I play the tracks in the playlist menu all I get is nothing or the first second of the track repeating itself over and over again.

Something wrong with the MP3s? Too big? Or what's the case with them?

Please help!