OCI8 using reference cursor

[eluser]Jbeetle[/eluser]
I have problem with using reference cursor.

Code:

public function GetUsers(){

        $cursor = $this->db->get_cursor();
        $this->db->stored_procedure("jile","get_roles" ,array
            (array
                ('name' => ':cRoles',
                 'value' => $cursor,
                 'type' => OCI_B_CURSOR,
                 'length' => -1)
                 )
             );

    }

throws:

ORA-24374: in file oci8/oci8_result.php, Line Number: 154

pls. help with solving this bug!