You didn't specify what operating system (or distribution, if you like) you are using, but I suppose you are talking about one of the latest Ubuntus (because of the Restricted drivers manager). So..did you try installing the package it wants?
sudo apt-get install linux-restricted-modules-2.6.22-14-generic
or trough Synaptic.
Have you done any system upgrades, that may have caused that? Graphics card driver upgrades?