Chances are they are ORB format, mp4 or other!!! Dare I suggest it, but a super audio app that will play pretty much everything & is free is QCD:
http://www.quinnware.com/ If you kike it, you might even want to make it your default audio player.
I beat u 2 the post Peerless but I decied to delete it after editing b/c of slow contact. Like my brain sometimes. lol