您输入的数量值无效。数量值必须是大于或等于1的整数

Question

我已经将自定义购物车上传到paypal，因此客户可以使用payapal付款，但每次我尝试使用它时，我在paypal网站上收到以下错误：

“您输入的数量值无效。数量值必须是大于或等于1的整数。”

这是我的代码：

    <form id = "paypal_checkout" action = "https://www.paypal.com/cgi-bin/webscr" method = "post">
        <input name = "cmd" value = "_cart" type = "hidden">
        <input name = "upload" value = "1" type = "hidden">
        <input name = "no_note" value = "0" type = "hidden">
        <input name = "bn" value = "PP-BuyNowBF" type = "hidden">
        <input name = "tax" value = "0" type = "hidden">
        <input name = "rm" value = "2" type = "hidden">

        <input name = "business" value = "my@mail.com" type = "hidden">
        <input name = "invoice" value = "0" type = "hidden">
        <input name = "handling_cart" value = "0" type = "hidden">
        <input name = "currency_code" value = "AUD" type = "hidden">
        <!--<input name = "lc" value = "EN" type = "hidden">-->
        <input name = "return" value = "http://www.#.com/page1.php?success=1&order=<?php echo $order_id; ?>" type = "hidden"> <!-- Change the domain as you wish -->
        <input name = "cbt" value = "Return to My Site" type = "hidden">
        <input name = "cancel_return" value = "http://www.#.com/page1.php?cancel=1" type = "hidden"> <!-- Change the domain as you wish -->
        <input name = "custom" value = "" type = "hidden">

        <div id = "item_1" class = "itemwrap">
            <input name = "item_name_1" value = "Rooms" type = "hidden">
            <input name = "quantity_1" value = "<?php echo $rooms; ?>" type = "hidden">
            <input name = "amount_1" value = "<?php echo $rooms_price; ?>" type = "hidden">
            <input name = "shipping_1" value = "0" type = "hidden">
        </div>

        <div id = "item_2" class = "itemwrap">
            <input name = "item_name_2" value = "Bath" type = "hidden">
            <input name = "quantity_2" value = "<?php echo $bath; ?>" type = "hidden">
            <input name = "amount_2" value = "<?php echo $bath_price; ?>" type = "hidden">
            <input name = "shipping_2" value = "0" type = "hidden">
        </div>

        <div id = "item_3" class = "itemwrap">
            <input name = "item_name_3" value = "Home" type = "hidden">
            <input name = "quantity_3" value = "<?php echo $home; ?>" type = "hidden">
            <input name = "amount_3" value = "<?php echo $home_price; ?>" type = "hidden">
            <input name = "shipping_3" value = "0" type = "hidden">
        </div>

        <input id = "ppcheckoutbtn" value = "Checkout" class = "button" type = "submit">
    </form>