I just installed this theme on a clean Wordpress 3.1 blog with absolutely no non-default plugins. The only thing I've done at all is change the table prefix. In the footer of theme, I'm seeing this:
Warning: array_key_exists() [function.array-key-exists]: The second argument should be either an array or an object in /home/cactus/public_html/wp-includes/widgets.php on line 858
How do I fix it?