Have you ever been debugging and just can't figure out what is wrong that one page? Sometimes Rails backtraces can't tell you the real reason behind your problems. There is a better way - look no further than the RFacebook Debug Panel:
The panel shows up when you use render_with_facebook_debug_panel in your controller actions. Its perfect for those bugs that are being caused by a simple misconfiguration.
This panel also shows up automatically in the Canvas when an exception occurrs. It will appear above the backtrace to give you a better idea of what the problem might be.