[b]Q:[/b] Help, my code to post to Facebook wall via FB.ui() has suddenly stopped working, it now just displays this error - 'An error occurred. Please try again later.', what's happened?, it used to work just fine!
[b]A:[/b] In the last few days Facebook have changed their rules and you now can't call FB.ui() without first passing a valid appID to FB.init() when you call it.. So if you used to call FB.ui() without first registering an app then this may well be what's causing you the problem.
To get around the problem, just register an app up on facebook and then make sure to pass your appID when you call FB.init(). All you have to do on Face book is register the app and take a copy of the AppId, you don't need to do any other setup and configuration on the application.
Hope this helps, we spent a good bit of time this morning trying to figure out what was broken!