Re: NVidia and recent 3.0.x Kernels
While you're waiting for them to answer you could try to debug the problem yourself. /var/log/nvidia-installer.log contains a lot info about what might went wrong. strace is your another friend.
Also, do you install kernel headers along with the kernel? It was always perfectly possible to install only the kernel binary and modules (actually modules are also not a requirement) and left headers behind. Check twice that you've got headers installed and have symlink to them in /lib/modules/$(uname -r)/build and /lib/modules/$(uname -r)/source.