No, I didn't rename the simulation space. It's called "space" and it's global in my program
Have you got the Quadbike example there? That has working trimesh collision... try importing the example mesh and seeing if that works in your code. It will at least tell you whether it's your code or an anomally with the mesh that is causing the problem. If you don't get collisions with the example mesh then you're going to have to do a line by line comparison with the example code to see where yours differs.