Database is an unsupported maintenance release for the current
  version

  Explanation:  The maintainance release number and the version
  number of the database that you just attached to forms an
  unknown combination.

  User Action:  Check to make sure that you are running with the
  correct versions of Oracle Rdb-supported database products for
  the SQL interface to Oracle Rdb.  Correct versions are listed in
  the Oracle Rdb Installation Guide.