Falling through mesh

I have a prob:

I created a level in 3d max, imported it and created a treecollision for it.
it worked and my objects fell on it. But now im changing it with another mesh and my collision doesnt work, how can be so, the difference only in loaded meshes?

make sure the normals are set right for the model, otherwise objects can pass through.

The normals look to be ok, are there any other suggestions?

trying pressing F3 and look at the collision mesh's

Show a screenshot with the debug lines (f3 pressed) so that we have a better idea and picture of whats going on! The collision box should be attached to the object node to work as required. I recon that could be the problem.

The problem is when i export a level created using loft