Fedora Core (aka Yarrow) uses /etc/X11/XF86Config as the primary X11 config. Please post that as requested (just not the -4 file), so that we can help you verify the drivers are setup correctly.
Enemy territory runs well for me, however it does suffer the occasional blank screen problem, and some crashes (which incidently DO leave your screen in the wrong resolution as you describe). To correct this when it happens, simply use ctrl-alt-+ to change to the desired resolution again. The blank screen happens infrequently but its not unusual. Deleting or rebuilding the config files for ET should fix that.
Did you install enemy territory before or after you installed the drivers?
"..the triumph of evil is for good men to do nothing."
VIDIA video driver RPMs for Fedora
:: see yum repo at livna.org