Thanks guys. But this has nothing to do with a wrong script or a hollow cube. It's this specific mesh not displaying.

You can run a completely blank level from within the WED without attaching any script. It uses a standard movement then. And content gets of course displayed, even without a hollow cube around. What not got displayed was this specific mesh.

Many thanks for the help

EDIT, correction, now i get it. Log2, you're right, MDL files needs to be loaded by script. How could i forget that. Aww, i totally mixed things here