Custom fields are not inserted/updated

Custom fields are not inserted/updated


My request is as below

https://crm.zoho.com/crm/private/xml/Accounts/insertRecords?authtoken=****&scope=crmapi&xmlData=
<?xml version="1.0"?>
<Accounts>
  <row no="1">
    <FL val="Account Name">ACD</FL>
    <FL val="Currency Used">USD</FL>
    <FL val="Area Code">103</FL>
  </row>
</Accounts>

custom fields 'Currency Used '& 'Area Code' aren't inserted. I tried updating an existing contact, all the fields other than the custom ones are updated.