Non-admin users can't run MMC on Windows Server 2008 domain controller

I have created some delegated privileges for IT administrators. One of the groups of people has some Active Directory permissions but is not server administrators or domain administrators. They also are allowed to connect with remote desktop on servers, domain controllers included.

When they connect with remote desktop on a DC running Windows 2008 R2 Enterprise edition, there is no problem. When they connect on a DC running Windows 2008 R2 Standard edition, they can't run MMC, UAC asks for a privilege escalation, and when password is typed, there is an error message saying something like (translation from French) "Logon Failure: The user has not been granted the requested logon type to the computer".

I just recently discovered the problem, and the only difference I see between the DCs are the Windows Server edition: Enterprise or Standard, but there may be others.

Has anyone an idea on why I have this problem? Or how to solve it? Or at least how to debug it?

Thanks