Site Deployment

We are using deployment scripts (vbs) that are scheduled to run through out

the day. Recently these have stopped working properly. The error received
is 
"80040154 class not registered", this happens on the authenticateasuser
call. 
The scripts run fine if the user is logged onto the server but fail when 
logged off. The server is Win2003 SP2. I have been told by the client that
no 
updates have been done to the server recently and I'm having trouble
trying 
to solve this problem. Any suggestions?