Error al crear vista indizada....

Hola a todos!

Mirad, tengo este error al ejecutar lo siguiente:


SET NUMERIC_ROUNDABORT OFF
GO
SET
ANSI_PADDING,ANSI_WARNINGS,CONCAT_NULL_YIELDS_NULL,ARITHABORT,QUOTED_IDENTIF
IER,ANSI_NULLS ON
GO

CREATE VIEW dbo.DV WITH SCHEMABINDING
AS
SELECT Numero, MAX(Valor) AS MaxValor, Count_big(Numero) as total
FROM dbo.DP
GROUP BY Numero, Valor
GO


CREATE UNIQUE CLUSTERED INDEX En_NumReg ON dbo.DatosValidez (NumReg)
GO



ERROR:
Cannot index the view 'dbo.DatosValidez'. It contains one or more disallowed
constructs.


No veo qué estoy incumpliendo... a ver si se os ocurre algo.

Muchas gracias de antemano

Salu2!!

Daniel R.