Cant play this song or that song

If it cant play songs I got from iTunes or songs from my personal library then what songs can it play? Could have used the money I spent on this app to get one that works :(
Cant go back and look for a song that works cause it crashes after it says song is DRM protected. I can play music fine on other dj apps. Its not fair paying for something that doesnt work AT ALL.

ChaunSee:D about Future DJ