w32tm error synchronizing

We just recently (1 month ago) upgraded our domain to Windows 2000. It’s a simple single-master domain, nothing fancy. None of my workstations or member servers (all Win2k) can synchronize their time. Some get errors in the event log, some don’t. When I run a w32tm -source -v, I get the following error:

W32Time: BEGIN:GetNT5DCAddress
W32Time: Member of an NT4 domain. Cannot synchronize.
W32Time: DC lookup failed. 15 min until lookup is allowed again.

I still have one NT4 DC, which used to be the PDC before our domain migration. I have configured my PDC emulator with an external time source. My secondary DC synchronizes fine with the main DC, thankfully (it recognizes that it’s in a 2000 domain). I have run a “w32tm -s” on a few workstations to no avail.

Any ideas?