You are using the Active Directory CMDLets coming with Windows Server 2008 R2 and Windows 7 Remote Administration tools to interrogate Active Directory Objects. When you print results of the Get-ADObjects CMDLets you get the output:
The given key was not present in the dictionary.
When launching Active Directory Administrative Center the Domain Controller chosen appears to be down. When you click on the domain controller you receive the error message “Failed to access the object. Check data availability or access permissions”:
When selecting “Change Domain Controller” you receive the error Message “Failed to retrieve Domain Controller information”: