Oracle - ¿Error 01722?

SELECT A.Descripcion

FROM Articulo A

INNER JOIN Suministra S

ON S.IdArticulo = A.IdArticulo

WHERE (S.IdArticulo, S.CodProveedor) IN (

SELECT IdArticulo, COUNT(CodProveedor)

FROM Suministra

GROUP BY IdArticulo

HAVING COUNT(IdArticulo) = 2)

;

SELECT DISTINCT a.Descripcion

  FROM Articulo a

  INNER JOIN Suministra s ON a.IdArticulo=s.IdArticulo

  WHERE a.IdArticulo IN (SELECT IDArticulo

          FROM (SELECT IdArticulo,COUNT(*) AS NUM

              FROM Suministra

            GROUP BY IdArticulo)

          WHERE NUM>=3);