There is no more source yet. This is all (except that mistake in ent_create). Here is whole project to download:
http://wolodo.yweb.sk/DROPS.rar
It is small..just about 180kB

So...it behaves like this: ball bounces with some energy loss. It beeps only when ball really hits the floor. Some time later it begins to beep also when the ball doesnt hit the floor, but just, when the camera looks at it. Id the camera looks away from ball, it beeps only when the ball hits the floor...strange smile
Maybe someone could test it. If you will not notice this bug, than the problem can be probably in my system. I will be gratefull if someone try to run this script and write me a repport.