I just installed the new version of Unity 4.3 and the new facebook sdk and I can\'t get it working.
I created the app on facebook, copied over the app id to the unit
Version 4.3.6 of the sdk should fix this problem. It's available here: https://developers.facebook.com/ We are still waiting for it to be approved on the asset store, so the only place to get it right now is from Facebook's site.
Note - it's still broken (5/2014) IF you use a Mac. Just follow the "Rafael solution", discover your hash properly from public void OnLoginComplete(string message). Cheers