I found out that when I add Domain/Administrators to the local Administrators group on the computer the error code now becomes 21. I also tried using WMI to shut down the computer instead of the Shutdown command and I got the same error. This would indicate that the problem has to do with Windows and not KiXtart. I have only tested this on my test domain, which only has 1 XP computer. I suppose I should try it on the real network and see if the problem changes. Is anybody aware of any specific aspects of the system policy which may be causing this problem?