I have installed the newest Nvidia drivers (v304.51) for my GeForce 8400GS video card (using the .run file taken from nvidia) but it is not recognized by Nvidia X server settings. It is still showing v195 as the driver version. I have tried using 'sudo apt-add-repository ppa:ubuntu-x-swat/x-updates' to no avail. I get an error: gpg: Invalid option "--primary-keyring"
I am running LinuxMint 9 Isadora. Is there an incompatibility between v304.51 and Isadora? If not, how can I force X server to use v304.51 instead of v195?