I'm trying to learn the DCE methods and so i created a new project with a ball moving on a cube used as a terrain, but whatever i try the jump method doesn't want to work. what are the requires in order to make it work? i tried to follow the DCEDemo but at this point the demo works and my code doesn't even if they are so similar.

i also tried to substitute it by applying a force directly up (ApplyAccel) to make the ball jump but it gives me a few problems with the height (he always jumps at different heights)

what could i do to make this ball jump?

here is the project (source+build): http://www.mediafire.com/?0kyzmmvnzdt