I think that there are some hardware restrictions for render targets I don´t know about.
The concept of this project is that each shader works independant from the others, this means that I just have to uncomment two lines and the shader is excluded from the project (with which I mean that the compiler doesn´t get any line of the code). Because of that it is very easy to make sure that there aren´t compability issues. And my biggest problem is that everything works fine on my system (8800gts 640mb).

The problems are the wrong rendered depthmap, the wrong/not/however rendered refraction map and the sometimes wrong rendered reflection map.
These are all using render to texture. The heat haze worked on more systems before I changed the resolution from 512*512 to 256*256.