If you think you've found a bug in Don't Starve, you should head over to our Bug Tracker and see if anyone else has had issue like your own. If yes, add to the discussion! If you can't find your issue, add a new one and we'll take a look at it as soon as we can.
If you wanted to report a Reign of Giants bug or technical issue, you should head on over to our Bugs and Technical Issues sub-forum. If you can't find your issue, feel free to add a new one and we'll check it out as soon as we can.