Sorry for my poor english... I have WindowsUpdate Server 2003 X64 Entwith Domain Controller role and I decided install on itExchange 2007. During install Hub Transport RoleI got a error message:"The operation could not be performed because object 'DCon that I run Exchange (VICO2)' could not be found on domain controller "second DC". After it installation failed.And also i can'tuninstall Hub Transport role! From Events logs: Event Type:Error Event Source:MSExchangeSetup Event Category:Microsoft Exchange Setup Event ID:1002 Date:28.02.2007 Time:8:38:57 User:N/A Computer:VICO2 Description: Exchange Server component Hub Transport Role failed. Error: Error: Could not find a directory entry for the server VICO2. and Event Type:Error Event Source:MSExchange ADAccess Event Category:General Event ID:2152 Date:28.02.2007 Time:8:46:05 User:N/A Computer:VICO2 Description: Process exsetupui.exe (PID=2060). An remote procedure call (RPC) request to the Microsoft Exchange Active Directory Topology service failed with error 1753 (Error 6d9 from HrGetServersForRole). Make sure that the Remote Procedure Call (RPC) service is running. In addition, make sure that the network ports that are used by RPC are not blocked by a firewall. RPC is runing, netdiagis clean, firewall is off. Help me!

Check you DNS Settings on all your servers, they should be pointing to the internal DNS server, and from nslookup you should be able to get authoritative answers for forward and reverse lookups of the following: domain.com, dc.domain.com, exchserver.domain.com, dc, exchsvr, dc ip, dns ip, exch ip If you arent getting those then you need to play with and fix DNS first. Once you are happy DNS is working, run the prepareschema, preparead and preparedomain tools and retry you install. With exchange 2007, if a setup fails the next time you run setup it picks up from where you left off so there should be no need to uninstall the role of the server. Also make sure you Domain & Forests are in either 2000 Native mode or 2003 Native mode.

You probably found your solution, but I found this article to be helpful with my similar problem.http://technet.microsoft.com/en-us/library/bb426952.aspxThe unattended install command is more helpful.