Ball getting stuck in surfaces and bouncing for no reason? Help!

I have been making an android game that uses the accelerometer to move a ball (a bit like Aerox). Sometimes on the surface it will start bouncing somehow and getting stuck in the surface. About a quarter of the ball sometimes gets in the surface and then it will start bouncing uncontrollably. I have a rigid body attached to the ball and the ball also has two scripts, one for moving and one for jumping. Please help I have no idea what is causing this or how to stop it. The movement script I found and changed parts of it.

Control (Movement) script: http://pastebin.com/Mwf94Nrk

Jump script: http://pastebin.com/cuCgVvBW

Please help!