SQL & PL/SQL

dear all

i have this table

hr_unit (node varchar2(20),
node_parent varchar2(20))

data in table like

node node_parent
------------------------------------------
1
2 1
3 2
4 3
5 4
6 4

---------------------------------------------------

i create vpd function like this

FUNCTION testvpdunit (schema_name IN VARCHAR2, object_name IN VARCHAR2)
RETURN VARCHAR2
IS
l_vpd VARCHAR2 (32000);
BEGIN
l_vpd :=
'1=1'
|| ' start with a.node = 3
connect by a.node_parent = prior a.node';
RETURN l_vpd;
END;

and add ploicy
using this

BEGIN
DBMS_RLS.add_policy ('hrmstest',
'hr_unit',
'unit_ploicy',
'hrmstest',
'VPDPLOICY.testvpdunit'
);
END;


-----------------------------------------------

when i make select on this table
i have this error ORA-28113: policy predicate has error.


any one have explanation for this error and is their problem when make connect by..start with in same table we have ploicy on it

thanks