The kernel interface layer of the NVIDIA kernel module must be compiled specifically for the configuration and version of your kernel. If you upgrade your kernel, then the simplest solution is to reinstall the driver.
ADVANCED: You can install the NVIDIA kernel module for a non running kernel (for example: in the situation where you just built and installed a new kernel, but have not rebooted yet) with a command line such as this:
sh NVIDIA-Linux-x86-1.0-6629-pkg1.run --kernel-name='KERNEL_NAME'
Where 'KERNEL_NAME' is what `uname -r` would report if the target kernel were running.