I successfully installed the nvidia driver and toolkit for cuda 5 (but not the samples) on a 64 bit Ubuntu 12.04 box. The samples failed to install even though I previously
Consider installing CUDA 5.5 in Ubuntu 12.04. The 5.5 release has special leverages to install it as a debian package. See the following links,
https://developer.nvidia.com/content/cudacasts-episode-5-install-cuda-55-linux-package-manager
https://developer.nvidia.com/cuda-downloads
It is truly much easier than all that you have tried till now ! personal experience ! :-)