Go into the Add/Remove Programs (or whatever it is called in English ) and add the Kernel sources there first, before you can get the updates from YOU...

1) Open YaST (it will prompt you for the root password)
2) Go to Software section (the default on my set-up)
3) Go to Software Management
4) Choose "Selections" from the drop down Filter list.
5) Towards the bottom of the list is the "Kernel Development" group. Check this.
5a) YaST should automatically check the "C/C++ Compiler and tools" section as well.
6) Click on Accept. You will probably be prompted to insert one of the CD's or the DVD.

Once the packages have been downloaded, go into YOU and get it to download the latest Kernel Source updates if there are any - the package manager only loads the latest sources available in your repositories, which by default will be the ones delivered on the original CD. If you have received any Kernel security updates, YOU will now automatically pull down the latest source code to match the installed Kernel for you.

The nVidia drivers wizard checks the source code it is using for linkage information against the installed Kernel. If they do not match, it cannot install the drivers.