[mythtv-users] Can't turn off screen blanking

[Don]

I've installed MythTv V-.20 on a Fedora Core 6 box, but cannot seem to 
turn off the screen blanking feature.  After a few minutes of idle 
display, the screen goes blank.  Using Jarod's guide, I have "xset 
-dpms" included in the autostart script, but I don't think it's 
working.  Running it manually, I get this error message:

[mythtv at danson ~]$ xset -dpms
server does not have extension for -dpms option
[mythtv at danson ~]

...but the man page for xset has the option.  Any clue on what I'm 
missing?  Thanks,

Don

PS - screen saver is turned off and the kde claims that my system does 
not support power saving.