gnome-control-center is not able tho set monitor brightness

I am on Ubuntu12.10 Quantal which is running from a USB-stick, created with usb creator. The system has the latest updates to today the 18.7.2012

The problem is that it is not possible to set the screen brightness of the system with

System Settings -> Brightness and Look

there are just no options for this.

I would like to look not the whole day in a flash light.

Steps to reproduce

1.Download the latest live cd amd64 on Quantal
2.Install it with usb creator from a Ubuntu12.04 64bit system
3.Start the computer with the prepared usb stick
4.run the 12.10 from usb stick in live mode
5.Open system settings
6.Choose Brightness and Look
7.See the missing brightness adaption option

The also attached XSessionErrors.txt shows that problem

(gnome-control-center:22334): screen-cc-panel-WARNING **: Error getting brightness: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such interface `org.gnome.SettingsDaemon.Power.Screen' on object at path /org/gnome/SettingsDaemon/Power
(gnome-control-center:22334): screen-cc-panel-WARNING **: Error getting brightness: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such interface `org.gnome.SettingsDaemon.Power.Screen' on object at path /org/gnome/SettingsDaemon/Power
(gnome-control-center:22334): background-cc-panel-WARNING **: Could not load /usr/share/themes/Adwaita/index.theme: No such file or directory
(gnome-control-center:22375): screen-cc-panel-WARNING **: Error getting brightness: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such interface `org.gnome.SettingsDaemon.Power.Screen' on object at path /org/gnome/SettingsDaemon/Power
(gnome-settings-daemon:19230): media-keys-plugin-WARNING **: Failed to get old screen percentage: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such interface `org.gnome.SettingsDaemon.Power.Screen' on object at path /org/gnome/SettingsDaemon/Power
(gnome-settings-daemon:19230): media-keys-plugin-WARNING **: Failed to get old screen percentage: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such interface `org.gnome.SettingsDaemon.Power.Screen' on object at path /org/gnome/SettingsDaemon/Power
(gnome-settings-daemon:19230): media-keys-plugin-WARNING **: Failed to get old screen percentage: GDBus.Error:org.freedesktop.DBus.Error.UnknownMethod: No such interface `org.gnome.SettingsDaemon.Power.Screen' on object at path /org/gnome/SettingsDaemon/Power

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: gnome-control-center 1:3.4.2-0ubuntu6
ProcVersionSignature: Ubuntu 3.5.0-4.4-generic 3.5.0-rc6
Uname: Linux 3.5.0-4-generic x86_64
ApportVersion: 2.3-0ubuntu4
Architecture: amd64
CasperVersion: 1.319
Date: Wed Jul 18 13:40:16 2012
ExecutablePath: /usr/bin/gnome-control-center
LiveMediaBuild: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120718.1)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-control-center
UpgradeStatus: No upgrade log present (probably fresh install)