When opening MPE from the Amazon appstore app, I get a message saying I no longer have the Amazon appstore app on my device. Obviously I do have it though. With amazon appstore customer support, I have completely removed MPE, and the whole Appstore, then reloaded everything and rebooted my phone. It worked for 3 seconds then I got the message again. I will attach the message, but I don't know if that will help. If you go to amazon and look the game up, check the 1 star ratings. They are growing and the comment will give you more customers with this same issue. Amazon says it's a developer issue. I also have a Android tablet and an Xbox that don't have any problems with the new update.
My exact device is a Blu Studio XL