When asking a question like this it helps to add what distro you are running & a basic rundown of your system's hardware. Even better, go to your Linuxquestions.org config page, (on any page, scroll down to find "My LQ" on the right & click "Edit Profile") & enter all your details there.
Have you tried uninstalling fglrx & seeing if the problem still happens?
Check out
http://xoomer.virgilio.it/flavio.sta...-supported.txt for a complete list of chipsets supported by the fglrx driver.