If the subject condition happens to you, reset your site preferences. Open a CMD prompt on the sever hosting the local DFS root replica, and type the following command:
Dfsutil /insite:\\domain.com\dfsroot /SET
NOTE: The /insite switch is NOT documented.
NOTE: The Dfsutil.exe tool is part of the Windows 2000 Support Tools. Install the Windows 2000 Support Tools by double-clicking Setup.exe in the Support\Tools folder on the Windows 2000 Professional or Windows 2000 Server CD-ROM.