Erro Procedure Interbase.

Estou tentando executar este SQL de criação de uma procedure e está me dando um erro de:

SQL Error Code = -206
Column Unknown
VCOMPET

SQL:

SET TERM @ ;

/*********************************************/
/* Gera Corte */
/*********************************************/

CREATE PROCEDURE GERA_CORTE ( pCODSET Integer, pANO Integer, pMES Integer )
AS

DECLARE VARIABLE vCOMPET CHAR(10);

Begin

vCOMPET = ´28/´ || :pMES || ´/´ || :pANO;

/* Mestre */
INSERT INTO PARCORUSU ( CODUSU, CODSET, ATECOM )

SELECT DISTINCT PARARQUSU.CODUSU,
PARARQUSU.CODSET,
vCOMPET AS ATECOM

FROM PARARQUSU INNER JOIN PARARQHID ON
( PARARQUSU.CODSIT = PARARQHID.CODSIT )
INNER JOIN PARARQFAT ON
( PARARQUSU.CODUSU = PARARQFAT.CODUSU )
INNER JOIN PARARQHID ON
( PARARQUSU.CODSIT = PARARQHID.CODSIT )

WHERE ( PARARQHID.IMPCOR = 1 ) AND
( PARARQFAT.DATPAG IS NULL ) AND
( PARARQFAT.MES <= :pMES ) AND
( PARARQFAT.ANO = :pANO) AND
( PARARQUSU.CODSET = :pCodSet );

/* Detalhe */
INSERT INTO PARFATCOR ( CODUSU, ATECOM, ANO, MES )

SELECT PARARQUSU.CODUSU,
vCOMPET AS ATECOM,
PARARQFAT.ANO,
PARARQFAT.MES

FROM PARARQUSU INNER JOIN PARARQHID ON
( PARARQUSU.CODSIT = PARARQHID.CODSIT )
INNER JOIN PARARQFAT ON
( PARARQUSU.CODUSU = PARARQFAT.CODUSU )
INNER JOIN PARARQHID ON
( PARARQUSU.CODSIT = PARARQHID.CODSIT )

WHERE ( PARARQHID.IMPCOR = 1 ) AND
( PARARQFAT.MES <= :pMES ) AND
( PARARQFAT.ANO = :pANO) AND
( PARARQUSU.CODSET = :pCodSet );

end @

SET TERM ; @