Users sent to blank page if error with Paypal

We want users to be able to checkout with Paypal Express as simple as possible, however MarketPress seems to take users to a blank page if a user doesn't enter in perfect Zip-code information. (The zip code passes the Shipping Page's validation checks because it's the right # of characters, but in reality the zip doesn't match the city)

For example:
If I enter in totally valid information, but enter in the wrong zip code and click "Continue Checkout" I'm taken TO A BLANK PAGE, and have to click "Continue Checkout" to see the Paypal error message... Is there a potential fix for this? Seems like the error message should appear on the shipping page since other fields like email, state, etc. are validated on that page...