When you configured your kernel, you didn't say "yes" to CONFIG_MTRR. It's under "Processor type and features", at least in menuconfig. It's labeled "MTRR (memory type range register) support". Enable that and recompile your kernel. You will probably need to also recompile NVIDIA_kernel after you boot the new kernel.
But that should just be a warning... as for the error, it worked before the kernel upgrade, I assume? Is there anything in dmesg or /var/log/messages from NVRM about it?