When you first install and configure the ADC in a Windows 2000 forest, the ADC extends the Active Directory schema, creates objects in the Active Directory Configuration container, and creates the Exchange Services and Exchange Administrators security groups.

In order to successfully accomplish these tasks, you must be logged on as a member of the Schema Administrators group, Enterprise Administrators group, and Domain Administrators group.

Subsequent installs of the ADC, in the same forest, do not require Schema Administrators credentials.