We're running NetWare 4.5 SP3 and ZfD 6.5 SP1b with no middle tier server.
Just one dedicated ZfD server. Clients are running 4.90 SP1a. When I
update them to the new ZfD Agent ( that came with ZfD 6.5 SP1b
I get this error:

1456: The Remote Management Agent is unable to read information from the
eDirectory server. Verify that the workstation object is valid and the
Middle Tier server is up and running.

I've already tried deleting the workstation object, rebooting the
workstation and re-importing with no success. The knowledgebase didn't
really help. Any ideas?