Receiving a bank page that shows only the header and main menu when checking out on Marketpress

We just recently are getting directed to a blank page that shows only the background, top header and main menu when clicking checkout through Marketpress. Items are indeed being added to the cart but the check out process doesn’t seem to be loading so a visitor can complete the transaction. I have checked this with different browsers such as Chrome, Safari and Fire Fox. I have also went through and disabled any plugins that may have an effect on it such as MP Checkout Recommendation and even the MP Floating Cart. The last order I have received was 06/24/2014 so this explains the lack of orders recently.

Any idea why this is happening? I’m losing business as of now.