I've got it working with catalyst 12.8 on Ubuntu 12.04.2 but the driver breaks quite a few things in Ubuntu.
Catalyst 13.3 beta 3 works great with Ubuntu 13.04 beta!!!! But when I open the miner it claims there is not GPU present at all! :/
Any ideas?
I don't know why that would happen.
Have you tried an older non-beta Catalyst on Ubuntu 13.04 beta? Or the new beta Catalyst on an older non-beta Ubuntu? That could help narrow down what the problem is.