Error from 1 DC when running dcdiag

[leddy]

I have 4 DC Win 2000 Servers

1 was NT 4 PDC
1 was NT 4 BDC with Exchange
1 Win 2000 SQL
1 Win 2000 ISA

When I run dcdiag on the PDC, SQL and ISA no errors

When I run dcdiag on the exchange server I get LDAP and RPC errors
[Server name of the PDC] DsBind() failed with error 1722,
The RPC server is unavailable..


[PDC] LDAP connection failed with error 58,
The specified server cannot perform the requested operation..
Warning: PDC is the Schema Owner, but is not responding to LDAP Bind.

Any help on this problem

Leddy