exceeded maximum allowable equivalence number

  Explanation:  The number of join equivalences used in a  request
  exceeds  the  limit.   The  limit is 32 in Rdb versions prior to
  7.0, and it is 1024 in later versions.

  User  Action:   Break  up  the  query  into  separate  requests,
  materialize  the  results  of  each  request, and then join each
  result to get the intended result.  If temporary  table  support
  is  available  in  the version of Rdb you are using, you can use
  the temporary tables to store the result of each request.