Can't get rid of screen 'saver'

[Gianluca]

apparently there are some hardcoded defaults in the X server that need
to be overridden to remove the 10 minute blanktime.

just add the serverflags section in your config file as explained
here: http://xorg.freedesktop.org/X11R6.8.0/doc/xorg.conf.5.html and
it should be fine. the one affecting you is probably this:

Option "BlankTime" "time"
    sets the inactivity timeout for the blanking phase of the
screensaver. time is in minutes. This is equivalent to the Xorg
server's `-s' flag, and the value can be changed at run-time with
xset(1x) . Default: 10 minutes.

you might also want to get rid of all those others options
"StandbyTime", "SuspendTime" and "OffTime" just to be on the safe
side.

HTH,

g.