BUG #1455: pg_dumpall fails

The following bug has been logged online:

Bug reference: 1455
Logged by: Boris Makovecki
Email address: boris(dot)makovecki(at)abak(dot)net
PostgreSQL version: 8.0.1
Operating system: Windows 2K3 web server
Description: pg_dumpall fails
Details:

I'm trying to migrate postgre DB from 7.4 to 8.0. When I start pg_dumpall
(8.0) and connect it to 7.4 it fails with error:

pg_dump: SQL command failed
pg_dump: Error message from server: ERROR: cannot cast type "unknown" to
text
pg_dump: The command was: SELECT proretset, prosrc, probin, null::text as
proargnames, provolatile, proisstrict, prosecdef, (SELECT lanname FROM
pg_catalog.pg_language WHERE oid = prolang) as lanname FROM
pg_catalog.pg_proc WHERE oid = '17926077'::pg_catalog.oid

oid 17926077 stand for recursive function:

CREATE OR REPLACE FUNCTION meta.entity_inherit_from(int4)
RETURNS varchar AS
'DECLARE
id_e ALIAS FOR $1;
rez varchar;
a int4;

BEGIN
SELECT INTO a lng_inherit_from_fkeyi_ref FROM meta.entity WHERE
lng_entity_pkeyi=id_e;
IF a IS NULL THEN
rez= \'\' || id_e;
ELSE
rez=meta.entity_inherit_from(a) || \',\' || id_e;
END IF;
RETURN rez;
END;
'
LANGUAGE 'plpgsql' VOLATILE;

please advice,
regards,
Boris Makovecki
ABAK.NET