SBS 2008 not restarting through UI, but restarts with ShutDown.exe command

Hello,

The SBS 2008 server shutdown UI does not restart the server, but an event has been entered into the system log.  It only closes the admin user session.

If the dos command ShutDown.exe /r is used, the server reboots properly!

Any suggestion on how to make the shutdown UI work properly?

Thanks, Dominic