songs stopping in the middle when away from wi-fi

Whenever I try to listen to my songs on the app,if I put them on a loop, then they cut off at random times and exits the app, but only when I'm out of range of my wi-fi, it think it has something to do with the adds. 

Also, now I can't put my IPod into sleep mode, I have to leave it on, and open to media burner. Otherwise it just stops and when you open the IPod again, it has exited the app.