"ZENNW32.DLL is misssing the entry point nwappLoadOD."

We are getting the error
"ZENNW32.DLL is misssing the entry point nwappLoadOD."

I have found this in some other threads in this forum, but they did
not go
in a useful direction for me. This error message is appearing on a
WinXP Pro
workstation before the NWgina appears after boot up. Zen policies are
not
working.

The history of this error is that we installed SP1b on ZfD 4. We thenupdated our workstations from client 4.83 to 4.9 and afterwards the
Zen
agent to the MSI version shipping with SP1b. I have tried deleting the

installpath registry key as suggested in TID 2967507 and also followed
the
other suggestions. No luck. I also think I got the same error at some
point
after rolling back from 4.9 client to 4.83, without updating the
agent.

ZfDagent.msi will install fine on a clean machine that has not had the

previous version of the agent or client installed and policies will
work.