12.04 - Error while installing drivers

When I tried to install additional drivers in Ubuntu 12.02 via terminal,I got this error message:

sudo add-apt-repository ppa:ubuntu-x-swat/x-updates sudo apt-get update sudo apt-get install nvidia-current
[sudo] password for reidsr:
Error: need a repository as argument

Can anyone tell me what's wrong?

                      Reidar