Fórum Erro Procedure This operation is not defined for system tables. #404904

Galera eu tentei criar essa Store Procedure no Firebird 2.1 e deu o seguinte erro:
This operation is not defined for system tables.
unsuccessful metadata update.
STORE RDB$PROCEDURES failed.
Malformed string.



Store Procedure:
CREATE PROCEDURE NEW_PROCEDURE (
    dt_ini date,
    dt_fim date)
returns (
    prod_id integer,
    prod_descricao varchar(50),
    vend_id integer,
    vend_nome varchar(50),
    grupo_descricao varchar(30),
    tqtde numeric(18,3),
    faturamento numeric(18,2),
    tcobranca numeric(18,2),
    tretorno_cob numeric(18,2),
    saldo_cob numeric(18,2),
    prox numeric(18,2),
    inad numeric(18,2),
    vtotal numeric(18,2))
as
BEGIN
  FOR
    select
                p.prod_id,
                p.prod_descricao,
                v.vend_id,
                vend.vend_nome,
                g.grupo_descricao,
                ------------ Totalização -------------
                sum(coalesce(it.ven_qtde,0)) as tqtde,
                sum(coalesce(v.ven_total,0)) as faturamento,
                sum(coalesce(v.cobranca,0)) as tcobranca,
                sum(coalesce(v.retor_cob,0)) as tretorno_cob,
                sum(coalesce(v.saldo_cob,0)) as saldo_cob,
                sum(coalesce(v.retor_cob,0)+coalesce(v.venda_prazo,0)) as prox,
                sum(case
                    when coalesce(v.cobranca,0) > 0  then  cast((coalesce(v.retor_cob,0) / coalesce(v.cobranca,0))*100 as numeric(15,2))
                else
                   0
                 end) as inad,
                sum(coalesce(v.venda_total,0)) as vtotal
        from cx_itens it
        inner join cx_vendedor v on (v.cxven_id = it.cxven_id
                                      and v.vend_id = v.vend_id
                                      and v.dt_caixa between :dt_ini and :dt_fim
                                      and v.situacao = 'FECHADO'
                                      )
       
        left join vendedor vend on (vend.vend_id = v.vend_id)
        right join produtos p on (it.prod_id = p.prod_id)
        left join grupo_prod g on (g.grupo_id = p.grupo_id)
        where p.ativo = 'A'  and it.ven_qtde is not null
        group by p.prod_id, p.prod_descricao, v.vend_id,vend.vend_nome,g.grupo_descricao, p.ativo
        order by 5,1,4
    INTO :PROD_ID,
         :PROD_DESCRICAO,
         :VEND_ID,
         :VEND_NOME,
         :GRUPO_DESCRICAO,
         :TQTDE,
         :FATURAMENTO,
         :TCOBRANCA,
         :TRETORNO_COB,
         :SALDO_COB,
         :PROX,
         :INAD,
         :VTOTAL
  DO
  BEGIN
    SUSPEND;
  END
END