Don’t run sax2. If you run sax2 it will delete the xorg.conf created by “aticonfig --initial” and you will lose the configuration you had created with “aticonfig --install”. So don’t run sax2 unless you are willing to accept that loss.
What are you trying to configure? If you are trying to reduce your resolutation you can do it with xrandr. If using KDE (and assuming the proprietary driver is running) you can boot to X and then type in a terminal: “krandrtray” (no quotes) and then look for a small “monitor” icon in lower right corner. Right click on that and select “configure display”. Use that to configure things.
For the lxde desktop, I think the app is called “lxdrandr”. I’m not familiar with the gnome GUI version of the app.