[ODE] Problem with trimesh

["Charles Bühring"]

Ii have a trimesh, the floor of a room and i have some boxes which i place
somewhere above the floor.

I place eight boxes over each other with some distance between them.
When the boxes start falling and hit the floor i have a stack of boxes, but
after some time the lower boxes move/fall through the floor.

Another problem is that if the boxes hit the floor while rotating they fall
through immediately...

Can anyone tell me how i can fix this ? I just want the boxes on my floor (
which is a little uneven )to behave like in the boxstack-test.

Thanks alot for any help :)