php - paypal express checkout ipn order total

Question

I'm trying to integrate PayPal's express checkout option to my website. Although when I submit the form I get this error:

Error : Order total is missing.
Array
(
    [TIMESTAMP] => 2013%2d10%2d26T11%3a02%3a21Z
    [CORRELATIONID] => b560763f62a46
    [ACK] => Failure
    [VERSION] => 76%2e0
    [BUILD] => 8252112
    [L_ERRORCODE0] => 10400
    [L_ERRORCODE1] => 10001
    [L_SHORTMESSAGE0] => Transaction%20refused%20because%20of%20an%20invalid%20argument%2e%20See%20additional%20error%20messages%20for%20details%2e
    [L_SHORTMESSAGE1] => Transaction%20failed%20due%20to%20internal%20error
    [L_LONGMESSAGE0] => Order%20total%20is%20missing%2e
    [L_LONGMESSAGE1] => Internal%20Error
    [L_SEVERITYCODE0] => Error
    [L_SEVERITYCODE1] => Error
)

&CURRENCYCODE=USD
&PAYMENTACTION=Sale
&ALLOWNOTE=1
&PAYMENTREQUEST_0_CURRENCYCODE=USD
&PAYMENTREQUEST_0_AMT=
&PAYMENTREQUEST_0_ITEMAMT=
&L_PAYMENTREQUEST_0_QTY0=1
&PAYMENTREQUEST_0_AMT=
&L_PAYMENTREQUEST_0_NAME0=Fund+your+balance
&L_PAYMENTREQUEST_0_NUMBER0=rbl
&AMT=
&RETURNURL=http%3A%2F%2Fdomain.com%2Fincludes%2Fipn%2Fpaypal%2Fprocess.php
&CANCELURL=http%3A%2F%2Fdomain.com%2Faccount

I can't seem to find the issue...

Answer 1

Couple of problems

PAYMENTREQUEST_0_AMT is repeated twice

PAYMENTREQUEST_0_ITEMAMT and PAYMENTREQUEST_0_AMT are empty. You have to provide an amount you want to process. Your error message actually says this