Comment 2 for bug 578736

Looks like a version mismatch between the kernel module and the user-space X driver. The kernel module seems to come from Catalyst 10.4, the user-space driver comes from the fglrx-package included in Ubuntu.

I'd recommend uninstalling all versions of fglrx that you have installed, make sure that dkms doesn't have any old fglrx kernel module versions hanging around and then reinstall the driver, either Catalyst or the driver in Ubuntu, but not both.