I am experiencing a problem with the Worldpay payment gateway, when a user creates an account with the site and uses the Worldpay payment method it doesnt send any information through to WorldPay the first time, if you reattempt the information is sent through correctly and payment can proceed I cannot see any reason why this would be the case and this is my first time using Worldpay as a payment my clients usually use SagePay or PayPal which works fine.
The problem is only happening on new accounts and is not a persistant problem once registered and been through the process or used another payment gateway.
Any suggestions on how to solve this or what it could be thats causing it will be greatly appreciated

thanks
Pete