Apple Remote Desktop: Cannot Shut Down or Restart Client Computer at Login Window
With version 1.1 or earlier of the Remote Desktop application, you cannot use the Shut Down or Restart commands on a client computer that does not have a user logged in.
Symptom
If an Apple Remote Desktop client computer is at the Login Window, the Remote Desktop application cannot restart it or shut it down.
Solution
Update the administration and client computers to Apple Remote Desktop 1.2.