Following the TurnBasedRPG tutorial, part 7 references width and height arguments that aren't yet provided by the template code:
here
It says to change the width and height, but for me the game constructor is called like so: new FlxGame(0, 0, MenuState). That's how it was when I called flixel tpl to get started (after changing PlayState to MenuState). So that line in the tutorial is a little confusing. It should either say to add arguments for width and height, or to edit the width and height arguments in Project.xml.