I have a client that is using a brand new istall of Office 2003 with all
the latest Office and Windows updates. They are also using the latest
GroupWise 7 software to access the GroupWise 7 email server. They are
not able to reply to any messages using Outlook. They can forward the
messages, but not reply. The error message says Microsoft Office Word
The messaging interface has returned an unknown error. If the problem
persists, restart Outlook.

Of course this is an endless cycle.

There doesn't seem to be any reported issues of this. Any ideas?