The Security System detected an attempted downgrade attack for server DNS/dns.taco.COM. The failure code from authentication protocol Kerberos was "There are currently no logon servers available to service the logon request.
Check this: http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q126752 and this http://support.microsoft.com/default.aspx?scid=kb;EN-US;Q284850.
Even though you said nothing about it in your question (*AHEM*) I assume you are still having issues with your Win2k Server Domain Controller. From the sound of things, your issues lie with services, specifically NetLogon, and affiliated components. Go through and follow the second link I gave you above and make sure your registry reads the way the article says it should, and go in to your services and make sure that "Server", "Workstation" and "netlogon" are all set to automatically start. From there, go through your event viewer logs and see what else you can find. If you're getting lots of recurring errors, try to document them all and either post them here or search for documentation in the knowledgebase. And you might want to keep all of this stuff in ONE thread so the background to your issue is easily attained by those who wish to help but don't know what you've tried already.