In the Fedora case:
If you have tried with F14 18.104.22.168-38
kernels or olders, that's unlikely that anyone succeeded in using the proprietary nvidia driver with that kernel.
That was because that kernel was still built with debug enabled, so the nvidia kernel module failed to build with the error:
FATAL: modpost: GPL-incompatible module nvidia.ko uses GPL-only symbol 'debug_lockdep_rcu_enabled'
This problem was solved when using kernel-22.214.171.124-39.fc14 and later, because they are not compiled with debug information.
If you follow carefully the instruction provided there, this should work without problem: