Sure that playback was not running? (i.e. the user input log was triggered by mouse/keyboard moves)
Yep, closed MP at 1935, checked in taskmanager not running, also then left untouched for 15 minutes after stay awake test and standby was achieved ok, so it looks like powerscheduler is fine with XP.
I am running Vista as administrator account only, no user and UAC disabled.
Possibly looking in the wrong place for keyboard\mouse being active.
Be aware, i am using a mce remote keyboard (ehome driver) and a Logitech wireless mouse, althought this should not make a difference, if you need me to use a standard keyboard will do.
Cheers