ORA-1405 fetched column value is null Pro*C

Can anyone help?

ORA-01405: fetched column value is NULL

Oracle 7.2 on HP-UX
Code:

       struct
        {
           VARCHAR v_postalroute[5];
        } address_temp;


        EXEC ORACLE OPTION (ORACA=YES);

        oraca.oradbgf  = 1;             /* enable debug operations */
        oraca.oracchf  = 1;      /* gather cursor cache statistics */
        oraca.orastxtf = 3;       /* always save the SQL statement */
 

       EXEC SQL DECLARE cur_address CURSOR FOR
                SELECT postal_route
                FROM   pp_postplus p1, scott t1
                WHERE  p1.sns_key(+) = t1.sns_key
                AND    (address_type = 'M'
                OR      address_type is NULL)
                AND    mail_ind <> 'N'
                AND    zip = ':p_zip'
                AND    sub_type = ':p_subtype';

        EXEC SQL OPEN cur_address;

        EXEC SQL WHENEVER NOT FOUND DO break;

        for (;;)
           {
                EXEC SQL WHENEVER SQLERROR DO sql_error("Address Fetch");
                EXEC SQL FETCH cur_address INTO :address_temp;
                printf("\naddress: %s\n",address_temp.v_postalroute);