I am not very sure this will help or not but you can try. I had rebooting problem and installation problem of ATI driver for ubuntu 9.04.
Basically this is what I did and I could install ATI driver:
sudo /usr/share/ati/fglrx-uninstall.sh # (if it exists)
sudo apt-get remove --purge fglrx*
sudo apt-get remove --purge xserver-xorg-video-ati xserver-xorg-video-radeon
sudo apt-get install xserver-xorg-video-ati
sudo apt-get install --reinstall libgl1-mesa-glx libgl1-mesa-dri xserver-xorg-core
sudo dpkg-reconfigure xserver-xorg
Then I deleted /etc/X11/xorg.conf, then rebooted my computer to make sure everything was cleaned up.
Then I run this command in terminal:
sudo sh ./ati-driver-installer-10-1-x86.x86_64.run
Then after installed these drivers but BEFORE I rebooted my system I typed the following into the terminal.
sudo aticonfig --initial -f
sudo aticonfig --acpi-services=off
This anticonfig solved my reboot problem. I not sure this is command applicable to you or not.
I referred to this forum:http://ubuntuforums.org/showthread.php?t=1315199