Crash when hit P?

I wanted to test if I could make ragdolls on the fly. I made a cube, made a duplicate and split it into 2 and moved to another layer. I made the top cube (in the second layer) always add the bottom cube (in the second layer) - run once. I made a rigid body joint so it acts like ragdoll. I went back to the first layer, added an empty, and made this following logic:

(cube) collision with property: the ------ (empty) and ------(empty) add object Cube (from second layer.

I also made it so the cube will disappear when collision with the property “thing”.

Now why does it crash? Thanks

Project file : http://www.filefactory.com/file/d6cf7b/

Sounds like you are having the same problem as me. Here is the responses I got:

http://blenderartists.org/forum/showthread.php?t=125659