When you attempt to promote a Windows 2000 Server to a domain controller, Dcpromo issues the following:
Active Directory Installation Failed The operation failed with the following error The network location cannot be reached. For further information about network troubleshooting, see Windows Help.Make sure that you have network connectivty. If the network icon on the taskbar has a red "X", the cable is unplugged. You can also type ipconfig and see if the media state is Cable Disconnected.
If this is the first domain controller in a new forest, you may wish to finish Dcpromo by installing the Microsoft Loopback Adapter.