I got around that by using the poweroff program found here:
[url]http://users.telenet.be/jbosman/applications.html[/url]
It’s no longer being developed but it works perfectly on win 2k / xp.
Have not tested it with vista / 7
Edit: I should mention that I use the auto-poweroff feature and that if you have a domain controller to use that to try to shutdown the computer(s).