I've been doing some googling on this myself. From what I can tell this 1789 Error has been around for a long while showing itself in different places (XP, Vista) and it appears that no one knows exactly what causes the error. Rejoining the domain seemed to be the most common answer given, but did not fix the problem most times. I did find an article or two that suggested that improperly configured DNS could play a role. One solution was given that they had used their firewall as the DNS Server and changing it to the AD DNS Server fixed the problem. Someone else suggested running ADPrep.exe (located on Server 2008 CD) to add the new properties to your 2000 AD.

@Arend, please do post back on this. Glad to find someone here who has this environment.