I have a kid computer with same problem.
Problem : The screen doesn't sleep-standby-off with gnome-power-manager settings ok
Installation : 1-Ubuntu 10.10 2-Qimo packages
Computer : Toshiba satellite a10 Intel 852/855 gm graphic
Workaround : Terminal xset +dpms
I have a kid computer with same problem.
Problem :
The screen doesn't sleep-standby-off with gnome-power-manager settings ok
Installation :
1-Ubuntu 10.10
2-Qimo packages
Computer :
Toshiba satellite a10
Intel 852/855 gm graphic
Workaround :
Terminal
xset +dpms