Panda PhysX

I’m in need of some help with the cooking process. When cooking a custom model, the kitchen returns a status of 1, so it does work. But when loading the model in the convex sample (04_Convex.py), I replace the tetra model with my custom model, I get these assertion failures:

I am quite new to Panda, Python and PhysX, but just editing a filename can’t be the problem, must be the model. The egg model was exported from 3dsmax 8.
Please help.