Disable screen blanking during XBMC

I'm having a problem: the screen saver starts during the playing of movies in XBMC. Only XBMC is running and the screen blanks after 10min. I found the commands that disable it, but I still lack a way to do it permanently:

export DISPLAY=localhost:0.0
xset dpms 0 0 0
xset -dpms
xset dpms force on
xset -q

To make the changes permanent I added the following lines in the file

~/.xbmc/scripts/autoexec.sh

xset dpms 0 0 0
xset dpms force on
echo $(date) '~/.xbmc/scripts/autoexec.sh: Touching xset' >> ~/myxbmc_log.txt
xset -q >> ~/myxbmc_log.txt
echo $(date) '~/.xbmc/scripts/autoexec.sh: Checking screensaver:' >> ~/myxbmc_log.txt
gnome-screensaver-command --query >> ~/myxbmc_log.txt