Its important the less cluey of us to make a webpage with a link as places like yours dont allow hotlinking across forum pages.
luckily if you visit your site without leopard.zip then after the page with errors has loaded to ammend the url then it will download.
anyway looking at your ms3d file called koepel_leopard2a5 and all the others it appears that no textures have been applied at all to the model in any way and its comprised of seperate model files i guess u join at a later time in a final 3d build or with code.
If u made a temp texture and selected the whole models faces then applied that texture for now it would be visible in DBP.
If im not mistaken u can set the emissive properties to a valid colour ( black is a tone ) and you will see the model polys but with no texture.
The art of perfecting the faces to represent your texture map is referred to as UV mapping/wrapping or skinning.
A black art in itself if you ask me