How to work with Invoice API create a customer payment?

How to work with Invoice API create a customer payment?

I am trying to cal an API to create a customer Payment.

My Code is

<%{
    authToken = "<myauthtoken>";
    invoiceMap = { "invoice_id" : "489509000000031013", "amount_applied" : "10100", "tax_amount_withheld" : "" };
    baseUrl = "https://invoice.zoho.com/api/v3/customerpayments";
    jsonMap = { "customer_id" : "489509000000030001", "invoices" : "[" + invoiceMap + "]", "payment_mode" : "Cash", "description" : "", "date" : "2014-03-27", "exchange_rate" : 1, "amount" : "10100", "bank_charges" : "" };
    requestMap = { "authtoken" : authToken, "JSONString" : jsonMap.toString(), "scope" : "ZohoInvoice/invoiceapi" };
    responseMap = postUrl(baseUrl, requestMap,false);
    responseCode = responseMap.get("responseCode");
    responseText = responseMap.get("responseText");%>    
        <%=responseCode%><br/>
<%=responseText%><%}%>

but the response is




Can anyone help me and if I am doing anything wrong please let me know