plpgsql and COPY

Hi,

Y want to use COPY command in a PLpgSQL procedure like this:

CREATE FUNCTION integration_salarie () RETURNS integer AS '
DECLARE

hemp_r record;
i integer := 0;
emp_exist integer := 0;
hnom varchar;
hpnom varchar;
hpos integer := 0;
hcoddep varchar;

BEGIN

drop table tmphoremp;
create table tmphoremp ( MATRI char(10),
NOMPRE char(30),
CCONT char(2),
MDATREC char(8),
DATCLO char(8),
TYPCONT char(3),
SOCPAIE char(2),
HORSECT char(16)
);

COPY tmphoremp FROM ''/home/public/intrasec/import/HOPEMP12.trs'' USING
DELIMITERS ''\t'';

IF NOT FOUND THEN RETURN -1;
ELSE RETURN i;
END IF;

END;

' LANGUAGE 'plpgsql';

Y have always the response : CopyObjet: don't know to copy 610

What's wrong ?

Thanks for your response.
Joseph Bonnet.