different message size received from expected

  Explanation:  The message size set by VMS system when message is
  put  in the buffer and the size computed by the monitor (message
  header + the message length) are different.  This can be  caused
  by a multi- user environment, e.g.  5.1 image tries to attach to
  6.1 monitor.

  User Action:  Rollback/Abort