This is an interesting one:
You cannot open the Exchange Management Console (EMC) in Microsoft Exchange Server 2007. Additionally, you receive the following error message:
Active Directory server dcservername is not available Error message: A local error occurred
This problem may occur if the Windows profile of your user account is corrupted.
This problem may also occur if Exchange Powershell cannot connect to a server that has stored credentials. Exchange Powershell must connect to the server to retrieve forest information that is incorrect or that does not have correct permissions.