do not use add_theme_support('menus') in your functions.php. I already removed it from the current SVN copy.
Here's the answer from Andrew Nacin regarding the question if a theme needs this call in the functions.php:
This is incorrect. add_theme_support('menus') is an internal process only. *It should never be directly called.* Instead, the theme should be calling register_nav_menu(s) which will trigger add_theme_support('menus') internally.
Likewise, add_theme_support('widgets') is internal only. The theme should only be calling register_sidebar(s).