function lfCheckError(&$objFormParam) {
        $objProduct = new SC_Product_Ex();

        $arrErr = $objFormParam->checkError();

        if (!SC_Utils_Ex::isBlank($objErr->arrErr)) {
            return $arrErr;
        }
// added
         $arrAllShipping = $objFormParam->getSwapArray($this->arrShippingKeys);
        foreach ($arrAllShipping as $shipping_index => $arrShipping) {
            $year  = $arrShipping['shipping_date_year'];
            $month = $arrShipping['shipping_date_month'];
            $day   = $arrShipping['shipping_date_day'];
            if ($year != '' && $month != '' && $day != '' &&
                !checkdate($month, $day, $year)) {
                $arrErr['shipping_date_day'][$shipping_index] = 'お届け日が実在しません。<br />';
            }
        }
// added