panel_version=$(chroot /root /usr/bin/dpkg-query -W --showformat='${Version}' gnome-panel-data 2>/dev/null) || panel_version=""
-if [ -n "${panel_version}" ]
+if [ -n "${panel_version}" ] && [ -n "${USERNAME}" ]
then
chroot /root sudo -u "${USERNAME}" gconftool-2 -s -t bool /apps/panel/global/disable_lock_screen true
fi