Remote Administration mode is an administrative convenience, not a way of supporting remote applications. So, by default, ordinary users can't log onto a server in Remote Administration mode -- just like they can't log onto the console. Therefore, to allow this person to run Word, you'll need to edit the permissions to allow him or her to run the session. I've documented the procedure here.
That said, I don't recommend letting users log onto production servers not dedicated to serving applications. This goes double if the server is a domain controller. It leaves a big security hole and also exposes the server to faulty applications that could crash the server or require reboots.
This was first published in August 2005