Outer Right Join?

I’m looking for a three-table join.  The SQL that I have isn’t working.

companies table - list of companies
products table - list of products sold by those companies
contracts table - list of companies that hold ad contracts

I need to ask:

"Show me the queried product (i.e.: Screwdriver) listings with their company names that DO NOT have contracts"

SELECT DISTINCT ON ("listings"."product")
  "listings"."product", "companies"."name"
  FROM "listings"
  RIGHT OUTER JOIN "contracts" ON ("contracts"."companyid" = "listings"."companyid")
  LEFT JOIN "companies" ON ("companies"."scid" = "listings"."companyid")
  WHERE (("listings"."product" ILIKE '%screwdriver%' ESCAPE '\'))

The result works without the RIGHT OUTER JOIN in there.  When the RIGHT OUTER JOIN is in there, I get a hitlist of
zero. Currently I have no contracts in that table, so those two queries should be the same.  They are not.   

To repeat, I want any company’s products that are in the contracts table, to not show up.  “products with no contract”.
 

Any inside as to how I can get this to work, appreciated.


Cheers, Bee