My keyboard arrow keys aren't working to in some books. What do I do?

I always use the keyboard arrow keys in order to move pages, but for some reason in certain books when I try to use the arrow keys to change page, nothing is happening. Although the page will change if I click the arrows on screen, I still want to be able to use the keyboard keys, because they are more convenient. What do I do?

P.S. the arrow keys are working fine in all my other programs, so I figure its something to with Adobe Digital Editions.