You didn't need to go to all that trouble. You can always find the latest NVIDIA driver in
my PPA on Launchpad. Just remove the Nvidia driver you manually installed (run the package with --uninstall), add my PPA to your repository list, and install the driver again with the non-free driver tool. Then, you will get all of the advantages of the DKMS system without having to use the old Nvidia driver packaged with Ubuntu.