When playing a game in fb, how do I delete the box asking for access, cloudfront.net?

There is one game in FB where I get a box requesting access to store info on my pc.  I have been selecting deny and then I move on with the game.  However, a couple of days ago, I selected deny and nothing happens.  Consequently the screen is frozen and I can not move on with the game.  Not able to perform any activities.  I have to reboot the computer and move on to another game.  Not sure how to stop this box from popping up on my screen.  Help!