As I described in the title, some materials aren't rendered. I'm not sure, but I think it only happens if I "copy paste" or append objects with their materials. I can solve this problem by recreating the broken materials (but this is a tedious task).
The materials are visible in textured viewport. Only when I start the BGE they are invisible.
Here you can Download the .blend:
(it is a car game. on the left is a text editor where I describe the problem again)
in this picture you can see the Material which disappears.