title: php - PayPal Order Total is Missing
body: <p>I am currently integrating PayPal Adaptive Payments (Express Checkout) in the lightbox, on my website. Everything is going fine -> users can pay, but whenever someone paid for an item, using the express checkout, this is the response:</p>
  
  <p>API RESPONSE:</p>
  
  <pre><code>TIMESTAMP = 2014-03-06T20:10:30Z
  CORRELATIONID = 505b77f3bea1
  ACK = Failure
  VERSION = 97.0
  BUILD = 9917844
  L_ERRORCODE0 = 10400
  L_ERRORCODE1 = 10406
  L_SHORTMESSAGE0 = Transaction refused because of an invalid argument. See additional error messages for details.
  L_SHORTMESSAGE1 = Transaction refused because of an invalid argument. See additional error messages for details.
  L_LONGMESSAGE0 = Order total is missing.
  L_LONGMESSAGE1 = The PayerID value is invalid.
  L_SEVERITYCODE0 = Error
  L_SEVERITYCODE1 = Error
  </code></pre>
  
  <p>This is the script:</p>
  
  <pre><code>$nvps = array();
  $nvps["VERSION"] = "97.0";
  
  // Single-item purchase
  $nvps["METHOD"] = "SetExpressCheckout";
  $nvps["RETURNURL"] = "http://www.zerogravityprogramming.com/PayPal/Articles/DigitalGoodsExpressCheckout/App/success.php"; // server
  $nvps["CANCELURL"] = "http://www.zerogravityprogramming.com/PayPal/Articles/DigitalGoodsExpressCheckout/App/fail.html"; // server
  
  $nvps["PAYMENTREQUEST_0_PAYMENTACTION"] = "Sale";
  $nvps["PAYMENTREQUEST_0_NOTIFYURL"] = "http://www.yourdomain.com/PayPal/YourPayPalListener.php";
  $nvps["PAYMENTREQUEST_0_AMT"] = "$Price";
  $nvps["PAYMENTREQUEST_0_CURRENCYCODE"] = "USD";
  $nvps["PAYMENTREQUEST_0_ITEMAMT"] = "$Price";
  $nvps["L_PAYMENTREQUEST_0_NAME0"] = "$Desc";
  $nvps["L_PAYMENTREQUEST_0_NUMBER0"] = "$Item";
  $nvps["L_PAYMENTREQUEST_0_AMT0"] = "$Price";
  $nvps["L_PAYMENTREQUEST_0_QTY0"] = "1";
  $nvps["L_PAYMENTREQUEST_0_ITEMCATEGORY0"] = "Digital"; // specific to Digital Goods
  
  // Since it's a digital good (and not physical), we don't need a shipping address.
  $nvps["REQCONFIRMSHIPPING"] = "0";
  $nvps["NOSHIPPING"] = "1";
  </code></pre>
  
  <p>The <code>$Price</code>, <code>$Desc</code>, and <code>$Item</code> variables, all have a value - so that is not the problem.</p>
  
  <p>Can anyone figure it out?</p>
  
  <p>Thanks in advance :)</p>