AbleCommerce Shopping Cart Software

A customer created an order, paid for it with PayPal, and everything worked fine. Then the customer called me to add a product to the order. I added the product to the order and directed the customer to the PayMyOrder page. She went to the page and tried to pay with PayPal again. However, instead of redirecting to PayPal when she pushed the button, it went to the receipt page. The PayPal site never loaded. Back on the admin side of things, there was a PayPal payment on the order for $0.00 with the "Waiting for IPN" status.

I verified all of this by logging in as the customer and trying it for myself. My PayMyOrderPage ConLib control is in its original state, and I'm running AbleCommerce 7.0.7 build 14588. Is there a way to fix this behavior? Is this a problem with AC, PayPal, or how the two communicate?

Thanks

Along these same lines.. You cannot apply a gift certificate to a order once it is placed which makes no sense.

I was reading another PayPal thread, and I came across a piece of info that may be applicable here. Someone had mentioned that PayPal requires a shipping address to work properly. If my order in question had already been marked shipped, would that have changed the request sent to PayPal to something that doesn't work?