Goblin Tanks

I'm going crazy... There are two awesome goblin tank models- the blaster and the blitzer- in the model downloads section. Me and some other people have been having problems getting them to work. Namely, the model works in the map editor, but not in game. It disappears, leaving only a shadow texture. It is not selectable. How the heck do you fix this? I have asked on the mini-forum of the model but so far no one answered.
Somebody help me....

Danya