I used the previous post yesterday here to resolve why I could not get into the Roles Based Access Control web page. The reason I was trying to do that was to review where the service account was for this system as I was getting the error below.
Log Name: Application
Source: MSExchange RBAC
Date: 31/08/2011 9:56:43 AM
Event ID: 17
Task Category: RBAC
(Process w3wp.exe, PID 11872) "RBAC authorization returns Access Denied for user domain.local/Users/BackupServiceAcct. Reason: No role assignments associated with the specified user were found on Domain Controller server.domain.local"
The solution is to ensure that you add the Service Account you are using for backup into the Exchange Organisation Administrators group. You can do that using either the Roles Based Access Control tool in the Exchange 2010 console, or you can simply add them into the correct security group which I chose to do.
Symantec document this here if you want to read more.