I have HP ProBook with dual GPU, first integrated by Intel and second is Radeon 6470M. I have installed proprietary driver (fglrx) for AMD gpu and then run aticonfig to create xorg.conf. After reboot my X server cannot start and throws errors like "fail to switch libgl link files" and other. I have Oneiric x64.
This seems to be a common problem for those of us with ATI/Radeon graphics cards. See bug 285603.
From what I can tell, the proprietary ATI drivers cause problems with Xorg especially if they exist alongside the opensource ATI drivers.
Try uninstalling any proprietary ATI drivers (fglrx) and install the open-source ATI drivers instead. The open-source drivers are called 'ati' or 'radeon'.
This is a common problem, and the steps are pretty well documented.
Uninstall using the instructions on this page. Try the "Problem: Need to purge -fglrx" instructions first, and move to "Problem: Need to fully remove -fglrx and reinstall -ati from scratch" if necessary.
Then follow these instructions to install the Radeon driver.
If you really want the proprietary fglrx driver, you should still consider replacing the proprietary drivers with the Radeon drivers first, so that you can make your system stable first. Once your system is stable, then try experimenting with the ATI proprietary drivers. Stability first, otherwise your experimentation will become very difficult.