Trouble launching nvidia-settings

I never use the Linux distribution kernel and drivers package: I always customize my kernels for the machine they are running on, and I always install the NVIDIA drivers “manually”, via their official *.run package.

You may find the said packages in the Current graphics driver releases thread, or from NVIDIA’s drivers download page

You will need to uninstall your distro’s package first (as well as any corresponding nvidia-dkms package).