Help me please is very important!

Help plss I dun understand why ok here go my problem I was creating a ball and make it bounce all that it was going well with no problem but until I create a background on a new layer the background just follow the ball movement instead of not moving I dun get it why like that fot the list of code I got it from http://www.bit-101.com/tutorials/gravity.html plss help…all I wanted was for the background to stay still not following the movement of ball.