Save PDF to server with argument causes odd behavior

I'm using this with uc_rules on 'Order checkout is complete'. Creating and saving invoices to the server. The creating and saving part works, but the user is directed to a white page that only displays the argument (order id) that I'm passing into the view with the rule. I've tried a simple redirect rule with the same trigger, which worked for an afternoon, but does not now. That rule is now sending users back to cart and the order does not actually happen at all.