Install ati and Now Can't change resolution....

[Tom Hilbert]

Hello, I followed the steps from the wiki binary install link and
after a restart went to the
system configuration>>screen resolution  menu to change from the
1600X1200 that is now running back to a more reasonable 1260x960 and a
higher refresh.  I received this note:

"The X Server does not support the XRandR extension.  Runtime
resolution changes to the display size are not available."

What are my options?
Run xf86config from terminal??  That never seems to work for me in the past.
Thanks!!