Silver Fang - you'd confirmed in our offline conversation via support ticket that this is working for you now, but I thought I'd go ahead and reply here also in case it's helpful to those browsing the forum.
This appears to have been related to a temporary Facebook API problem.
Invalid responses from Facebook will crop up when their API slows down or has temporary issues. Unfortunately we can't give a much more descriptive error message than that in the app since we don't know the specific details of the situation. Sorry for the inconvenience.