When i’ve tryed to install the closed nVidia drivers, the installation exit with the seguent error:

-> The CC version check failed:
The compiler used to compile the kernel (gcc 4.1) does not exactly match the current compiler (gcc 4.2). The Linux 2.6 kernel module loader rejects kernel modules built with a version of gcc that does not exactly match that of the compiler used to build the running kernel.
If you know what you are doing and want to ignore the gcc version check, select "No" to continue installation. Otherwise, select "Yes" to abort installation, set the CC environment variable to the name of the compiler used to compile your kernel, and restart installation.

This happens because the Kernel was compiled with a different version of gcc. To solve this problem you have to write the following commands before to start the installer.

hp: # CC=gcc-4.1
hp: # export CC

Don’t worry because the effect of that commands is temporary. At the next reboot all come back to the default settings. Or simply use the following commands after the installation

hp: # CC=gcc-4.2
hp: # export CC

Substitute gcc-4.2 with your current gcc version.