Exchange 2010 Install fails at hub transport install $error.clear()

Hi guys. I'm installing Exchange 2010 for the 3rd time as my other configurations were not perfect. I did a safe uninstall on 2 of the three failed and the first one I accidentally killed the machine before cleaning it up properly. I have cleaned out my domain using ADSI edit though, and as far as I can tell it it sterile. Now, when I try to install Exchange 2010 on a brand new 2008R2 server it gets to the Hub Transport Role and fails. The error is:

Error:
The following error was generated when "$error.Clear();
if( ($server -eq $null) -and ($RolelsDatacenter 0ne $true) )
{
Update-RmsSharedIdentity -ServerName $RoleNetBIOSName
}
" was run: "Database is mandatory on UserMailbox. Property Name: Database".

Database is mandatory on UserMailbox. Property Name: Database

I really need help with this one guys, so big thanks to anyone that can offer assistance.

Thanks