In <1995Apr19.114350.3044 AT draper DOT com>, mersch AT uni-muenster DOT de 
(Reinhard Mersch) writes:
>Hello,
>
>I just want to tell you about an error I encountered today (AIX client
>V1R2M7, AIX server V1R2M5). The client got the error message
>   "ANS4029E Session rejected: Communications protocol error"
>during backup and archiving. dsmerror.log further said:
>   "fsCheckAdd: received more than one response"
>This error turned out to occur only when processing files in ONE of the
>client's file systems. Further investigations showed that the server knew
>this file space TWICE (it showed up twice on response to "QUERY FILESPACE").
>
>The problem was solved by doing a "DELETE FILESPACE" on the server, which
>deleted both file spaces. I do not know, what to do, if one cannot afford
>loosing all backups and archive copies of the file system.
>
>Reinhard Mersch                     Westfaelische Wilhelms-Universitaet
>Universitaetsrechenzentrum, Einsteinstrasse 60, 48149 Muenster, Germany
>E-Mail: mersch AT uni-muenster DOT de                   Phone: +49(251)83-2488

I have had the same problem on 3 or 4 Macintosh clients.  We were never
able to find the cause but we suspected it happened while the hard drive
was being replaced.  It was reported to IBM, but no fix has been
developed (thay can't reproduce it and neither can I).

If it happens again, call IBM support!  There are tools to use to fix
the problem without deleting both filespaces.

Bill Colwell
C. S. Draper Lab
Email: BColwell AT draper DOT com
Voice: 617-258-1550