TABLE FUNCTION, ERROR: WRONG RECORD TYPE IN RETURN NEXT

Hi,
I having some problem with table function that returns set of 'type',

Error says: Wrong record type supplied in return next, why it so?
Thanks.

type:
public.my_type ( name varchar(800), ncount int4, total int4 )

function:
CREATE FUNCTION public.doit() RETURNS SETOF public.my_type AS '
DECLARE
rec RECORD;
BEGIN
FOR rec IN
SELECT public.getname( fullname ) AS fullname,
COUNT( userid ) AS ncount,
ROUND(10000.0 * CAST( COUNT( userid ) AS bigint
) / 10000, 0) AS total
....
LOOP
RETURN NEXT rec;
END LOOP;
RETURN;
END;