You should compile the nVidia module with the same version of GCC you used to compile your kernel. You compiled your kernel with version 3, so use the same version to compile the nVidia module.
I think you can also do IGNORE_CC_MISMATCH, but that's probably not a good idea.
"Floating in a dream-like state, I am the emporer of a parallel universe." --Arch Enemy
My xorg.conf file