After searching “http://www.linuxquestions.org/”
I fund a solution. The problem was that installing the kernel source was not enought. I had to do this as well:
1. cd /usr/src/linux-<kernel_you_are_using>
2. make mrproper
3. cp /boot/config-<kernel_you_are_using> .config
4. make oldconfig
5. make dep
6. edit include/linux/version.h and remove “custom” from
#define UTS_RELEASE "2.4.20-28.8custom"
After this nVidias installer worked fine!