I've been having this same problem. I've tried deleting and reinstalling the app from both general settings and from the home page. I've tried logging in from other various places both public and at friends and still nothing. Did you find any fixes for this problem? I even downloaded the most recent update today hoping it would solve this bug, but still no help. I can log into the Facebook app directly, I can log into Facebook through the internet on my iPad, but it won't log in from General Settings. I've found it's blocking some of my apps and game friends connected through Facebook. Every time the bubble pops ups that I need to allow the app through Facebook in General Settings it takes me back to the settings area where it won't connect.