And once again I solve the problem my self.
This was what went wrong: when you compile cdrtools, a library called "libscg" also get's compiled. This library needs the kernel 2.4.x headers to compile. But when I installed 2.6, I made the symlink "/usr/src/linux" point to "/usr/src/linux-2.6.0". The library won't compile with the headers of the 2.6.0 kernel, so the compilation of the library faild.
The subsecuent linking of the other programs thus also faild.
Thank god I still had the old kernel sources lying around