Problem with implementing paypal's Express checkout API?

I'm doing e-commerce application, there m implementing paypal's Expresscheckout API for online shopping.I have created sandbox test account also. but if i call setexpresscheckout API I'm getting the order total missing error:

Here is my code snippets

<form method="post" action="https://api-3t.sandbox.paypal.com/nvp"> 

<!-- UNPROTECTED VALUES. DO NOT USE IN PRODUCTION --> 

<input type="h开发者_C百科idden" name="USER" value="xxxxxxx.gmail.com"> 
<input type="hidden" name="PWD" value="tttttttt"> 
<input type="hidden" name="SIGNATURE" value="hidden"> 
<input type="hidden" name="VERSION" value="50.0">
<input type="hidden" name="PAYMENTREQUEST_0_PAYMENTACTION" value="sale">
<input name="PAYMENTREQUEST_0_AMT" value=19.95">

<input type="hidden" name="RETURNURL" value="http://www.xyz.com/">
<input type="hidden" name="CANCELURL" value="http://www.xyz.com/">

<input type="hidden" name="PAYMENTREQUEST_0_CURRENCYCODE" value="USD"> 
<input type="submit" name="METHOD" value="SetExpressCheckout">

</form>

If anybody knows how to solve this, please let me know.

---

You are using PAYMENTREQUEST_0_AMT however your version (50.0) is very old and I don't think that supports multiple payments.

try upping the version to 65.0 or use the old way of specifying amount, I think it is just "AMT"