Domain was an INTERVAL data type

  Explanation:  This message is used as a subcode to
  SQL$_DOMNOTBCK.  It indicates that the offending domain was a
  new subtype of DATE.  Specifically, INTERVAL data is not stored
  in the previous (ADT) format and cannot be interpreted in the
  same fashion.

  User Action:  The database cannot be exported WITH NO EXTENSIONS
  until this domain is removed completely.