I've reworked the pages so many times that I can't see them any more. Unfortunately, updating the server behaviors didn't fix the problem. The only improvement is that PayPal no longer goes to a blank page but instead goes to the checkout failure page. I added the display error code to the top of the pp_confirm page and the checkout_failure page and no errors show. Are there other pages I should add the code to? Do you have any other ideas?