From my kernel boot message:

Its not a huge problem, but it'll probably affect credibility slightly in bug reports and such. How do I get the module not to taint the kernel should I recompile again? I have 2.6.3.

I think it just means the licence is not a "free" one, and has nothing to do with the code itself. Someone correct me if I'm wrong though.

Except it TAINTS the kernel, which isn't good on the bug reports.

Notice how it says the license is what taints the kernel. The Linux kernel is released under the GPL, right? The nVidia drivers are not. It's saying you're loading a non-free software module which causes the kernel to not be 100% GPL. You can't get it to not taint the kernel, unless you can convince nVidia to GPL their drivers.

There is open-source Nvidia drivers, if you use those instead of the official ones you wont get that error, but its not really a big deal.

Yea, that is pretty anoying, huh? Your anal just like me.... I always try to clean up the boot process, but trust me, I've been seeing that for the past year or so, and it's not going to go away.... I'm sure you could make it dissapear if you were resourceful enough and had some time on your hands... I get messages about can't find module ide-scsi when that crap isn't even in my kernel..... It expects to have a scsi emulator when you want to run full-support atapi but still whines about it anyway.... I don't even bother anymore.... If it boots with no adverse effects, who cares..... That stuff flies by so quick anyway, Just pretend like you didn't see it.... Alot of stuff can be fixed with your modules.conf or modules.dep files but with nvidia, it's a little harder... It could be done tho... Nothing is imposible with Linux... Just ransack all your nvidia files until you find the refrence to that line....