Active directory replication

Not sure if this is the right place, but here goes....

I just installed a new domain controller into an existing Windows 2000
Domain. The operations master houses the microsoft exchange
application. Active directory replication works for all objects
except the exchange objects. I am getting 1153 errors in the event
viewer logs. They look like this:
"Class identifier 1710883821 (class name msExchGroupWiseConnector) has
an invalid superclass 196659. Inheritance ignored.".

Hope someone can help.
Mike