Function return type does not match

Hi I modified my function to:

CREATE FUNCTION buscablista (character varying, character varying) RETURNS
SETOF cabezalista
AS '

select * from cabezalista where idlista like CAST($1 AS CHAR(20)) and
idlibro like CAST($2 AS CHAR(6));

' LANGUAGE sql;

But when called it gives me the error:

ERROR: Query-specified return tuple and actual function return tuple do not
match
ERROR: Query-specified return tuple and actual function return tuple do not
match

As i see it, the return types are the same (cabezalista) whic is a table in
my database... I think something went wrong when i dropped and re created
the table in order to add a column and do some other minor changes (like
changing char(6) to char (7) in some columns)

Thanks a lot
JuanF