You didn't mention, what kernel version, you are running. I know you have a kernel installed, and you will need sources for THAT
version, not for some other version.
To find out, what version your kernel is, run
su -c 'grep kernel\ version /var/log/kernel/info |cut -d: -f4|tail -n 1'
It will ask you for your root password, then find any line in /etc/log/kernel/info that has the world kernel version
in it. Then print the part from the 4th to the 5th of last of theese lines.
Then go to www.kernel.org
and download the sources for that version.
unpak them using:
tar xjf kernel-souce-files
Now the Nvida drivers, should find the sources, and compile with out problems.
Kernel sources are those used to bild the kernel. It boots at startup, and handles all hardware actions - such as reading/writing to a disk such. That is way I was sure, You already had a kernel. People says they install Linux, put technicly the kernel is linux.
It is needed to do such a simple ting as executing a program. With the kernel, you have nothing