When trying to shutdown Server 2003 with the shutdown command, you get:
The machine is locked and can not be shut down without the force option.(1271)
Windows reports the machine to be locked because there is another user logged on who has locked Windows. You can also get this message in error, in which case there’s a hotfix available. However, as Windows Server 2003 is no longer supported, I’d recommend upgrading instead.
To get around the machine being locked and shutdown the machine anyway, run the shutdown command with the -f switch.