I am currently in the process of replacing our 2 domain controllers with shiny new servers and operating systems. Our schema is at the 2003 level, but soon I'll have it at the 2008 level, once both new DCs are installed and the 2 old DCs are demoted and shutdown. I have Windows Server 2008 R2 Standard 64-bit installed on both servers. I have UltraVNC 188.8.131.52 installed as well. VNC works fine with the normal password authentication, but it fails using MS Logon authentication. It gets the message about no valid password set. I have MS Logon working on several other servers, including the old DCs, so it's not like I don't know how to set it up, but they are all running 32-bit versions of 2003 Server.
Besides the basic troubleshooting I've already done, what other things I can I look at to get this working right on Server 2008 R2 64-bit?