>Incidentally, the server on which this code runs is being upgraded from NT4 to 2000 server soon so your additional comment in this regard are appreciated!

Well there is nothing special with the upgrade to Windows 2000 Server.
However you should keep in mind that in Win2k there is no PDC & BDC. So there are some issues but they are well documented in the MSDN library and Win2k Srv help.
See:
Migration Domain Controllers to Windows 2000
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnntmag00/html/migrating0299.asp

Microsoft Windows 2000 Active Directory Technical Summary
http://msdn.microsoft.com/library/en-us/dnactdir/html/msdn_actdsum.asp

Check the Windows 2000 Server help
http://www.microsoft.com/windows2000/en/server/help/

Upgrading a Windows NT domain
http://www.microsoft.com/windows2000/en/server/help/sag_addeploy_17.htm

You can also use "Upgrade from NT" as keywords (ensure that you are doing all words search) for searching in Win2k help.

HTH