NMEXTDLL.EXE error on startup (Outlook 2k3)

[Jack Black]

Hi, all! Using Outlook 2k3 under XP/Pro (SP2+)... System also has
Groupwise 6.0.1 installed (unfortunately)...

After cleaning up some "issues" caused by Groupwise, I've wiped and
reinstalled Outlook 2k3. Upon startup, I get an error that says:
"The add-in 'nmdcext.dll' could not be installed or loaded."

This occurs on each and every reinstall I try (don't ask how many
times I've tried), and a search of TechNet yields nothing.

Anyone have any suggestions? I was finally able to get Outlook 2k3 to
run (without setting up email), but I still get this error at the
start of every 2k3 session. Any suggestions would be greatly
appreciated!

Thanks,
Jack