Just set up a Terminal Server, and when users of the “domain users” group attempted to log on, they received this error:

To log on to this remote computer you must have terminal server user access permissions

Here is the solution:
http://www.computing.net/answers/windows-2003/windows-2003-terminal-server/4298.html

go into the terminal server config, right click the connection and go to properties. In there you need to add the users that can terminal server in