Need urgent help to install MS Exchange 2010 on Windows 2008 R2 Standard edition.

Hi all,

I am installing ms exchange 2010 sp1 on windows 2008 R2 server standard edition.While installing I am getting the following error.Please help me trace out this issue.

Summary: 6 item(s). 1 succeeded, 1 failed.
Elapsed time: 00:00:36

Preparing Setup
Completed

Elapsed Time: 00:00:12

Hub Transport Role
Failed

Error:
The following error was generated when "$error.Clear();
 set-ExchangeServerRole -Identity $RoleFqdnOrName -IsHubTransportServer:$true -DomainController $RoleDomainController

" was run: "The domain is invalid. Property Name: Domain".

The domain is invalid. Property Name: Domain
Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.2.247.1&e=ms.exch.err.Ex88D115&l=0&cl=cp

Elapsed Time: 00:00:23

Client Access Role
Cancelled

Unified Messaging Role
Cancelled

Mailbox Role
Cancelled

Finalizing Setup
Cancelled