Latest proprietary AMD Catalyst driver version 12.9 cannot be used with Ubuntu 12.10 If you have a AMD Radeon HD 2xxx-4xxx series card.
Drivers for these cards are now available in a separate branch called legacy series. Unfortunately these legacy drivers (version 12.6) have not been updated to work with Ubuntu 12.10. Ubuntu 12.10 comes with xorg 1.13 while these drivers have support for older xorg 1.12.So if you want to install these drivers in Ubuntu 12.10, you have to downgrade to xorg 1.12.
To install these packages open the terminal and run the following commands
sudo add-apt-repository ppa:makson96/fglrx
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install fglrx-legacy
Remove these packages using the following commands
sudo apt-get install ppa-purge
sudo ppa-purge ppa:makson96/fglrx