ERROR: fmgr_info: function 24126: cache lookup failed

Hi.
Even after reading many messages in this list, I still have this
problem, so I ask for help. In this case, recreating the trigger didn't
fix the problem.

I have to timestamp records on every update or insert. I did the
following steps in this order:
1) created this table:
CREATE TABLE "tb_cargo" (
"id_cargo" int4 DEFAULT nextval('"sqnc_cargo"'::text) NOT NULL,
"id_familiacargo" int4 NOT NULL,
"ds_cargo" varchar(40) NOT NULL,
"dt_alteracao" timestamp,
CONSTRAINT "PK_cargo" PRIMARY KEY ("id_cargo")
);

2) created this function:
CREATE FUNCTION "atualizadtalteracaorefs"() RETURNS OPAQUE AS 'begin
NEW.dt_alteracao:=CURRENT_TIMESTAMP;
return NEW;
end;
' LANGUAGE 'plpgsql'
The table

3) created this trigger:
CREATE TRIGGER "ta_tb_cargo" BEFORE INSERT OR UPDATE ON "tb_cargo " FOR
EACH ROW EXECUTE PROCEDURE atualizadtalteracaorefs();

4) tried to insert data
ERROR: fmgr_info: function 24126: cache lookup failed

Guilherme Silva