If your Active Directory MMC utilities are slow to initialize, and run, or if they hang during initialization, DNS is not properly configured for the domain controller. It may be pointing to a DNS server that does not contain the SRV records for the domain, or there may be entries for domain controllers that can not be contacted.
To reslove the issue, verify that the SRV records exit in DNS. See Knowledge Base article Q241515 - Verifying the Creation of SRV Records for a Domain Controller.
See Q237675 - Setting Up the Domain Name System for Active Directory.
See Q247811 - How Domain Controllers Are Located in Windows 2000.