ERROR: Unable to load the kernel module 'nvidia.ko'. This is most likely
because the kernel module was built using the wrong kernel source files.
Please make sure you have installed the kernel source files for your
kernel; on Red Hat Linux systems, for example, be sure you have the
'kernel-source' rpm installed. If you know the correct kernel source
files are installed, you may specify the kernel source path with the
'--kernel-source-path' commandline option.
nvidia: version magic '2.6.11-12mdk 686 gcc-3.4' should be '2.6.11-6mdk 686 gcc-3.4'
So, the kernel complains because the driver you`ve builded used another kernel-source...
so, either you upgrade the kernel to 2.6.11-12mdk, or get 2.6.11-6mdk's source package... and try again...