title: paypal This transaction cannot be processed. The amount to be charged is zero
body: <p>Here is the code I used</p>
  
  <pre><code> $max_amount = 20;
              //$max_amount = $this-&gt;currency-&gt;convert($order_info['total'], $this-&gt;config-&gt;get('config_currency'), 'USD');
  
              $max_amount = min($max_amount * 1.25, 10000);
              $max_amount = $this-&gt;currency-&gt;format($max_amount, $this-&gt;currency-&gt;getCode(), '', false);
              $max_amount = $max_amount*100;
              $data = array(
                  'METHOD' =&gt; 'SetExpressCheckout',
                  'MAXAMT' =&gt; $max_amount,
                              'AMT'    =&gt; 1000,
                  'RETURNURL' =&gt; $this-&gt;url-&gt;link('payment/pp_express/checkoutReturn', '', 'SSL'),
                  'CANCELURL' =&gt; $this-&gt;url-&gt;link('checkout/checkout', '', 'SSL'),
                  'REQCONFIRMSHIPPING' =&gt; 0,
                  'NOSHIPPING' =&gt; 1,
                  'LOCALECODE' =&gt; 'EN',
                  'LANDINGPAGE' =&gt; 'Login',
                  'HDRIMG' =&gt; $this-&gt;model_tool_image-&gt;resize($this-&gt;config-&gt;get('pp_express_logo'), 790, 90),
                  'HDRBORDERCOLOR' =&gt; $this-&gt;config-&gt;get('pp_express_border_colour'),
                  'HDRBACKCOLOR' =&gt; $this-&gt;config-&gt;get('pp_express_header_colour'),
                  'PAYFLOWCOLOR' =&gt; $this-&gt;config-&gt;get('pp_express_page_colour'),
                  'CHANNELTYPE' =&gt; 'Merchant',
                  'ALLOWNOTE' =&gt; $this-&gt;config-&gt;get('pp_express_allow_note'),
              );
  
              $data = array_merge($data, $this-&gt;model_payment_pp_express-&gt;paymentRequestInfo());
              echo '&lt;pre&gt;';
              $result = $this-&gt;model_payment_pp_express-&gt;call($data);
  
              print_r($result);
  </code></pre>
  
  <p>The result of print_r($result) is</p>
  
  <pre><code>Array
  (
      [TIMESTAMP] =&gt; 2014-05-26T13:48:19Z
      [CORRELATIONID] =&gt; d5ff8073cbde
      [ACK] =&gt; Failure
      [VERSION] =&gt; 65.2
      [BUILD] =&gt; 11110362
      [L_ERRORCODE0] =&gt; 10525
      [L_SHORTMESSAGE0] =&gt; Invalid Data
      [L_LONGMESSAGE0] =&gt; This transaction cannot be processed. The amount to be charged is zero.
      [L_SEVERITYCODE0] =&gt; Error
  )
  </code></pre>
  
  <p>Whether I have to round up the values?</p>