Small oscommerce checkout page fix

If you go to [login to view URL] and add this tour into the basket, then go to the checkout page (/[login to view URL]) - change this to the page we are working on [login to view URL] then fill out the boxes and click on the Paypal Checkout link, the link doesnt take you to where it should. It just does nothing despite all the information being correctly filled in. Can someone please fix this link asap. Thanks. Chris