Hey... thanks for letting me know. I could be mistaken but I believe this is a problem with the All-In-One plugin.
They are using meta boxes on their settings page, which is fine, but they are using the 'add_meta_boxes' action hook to add their meta boxes, which is also fine, BUT this is a core WordPress hook that should pass 2 parameters: the page and the object ($post, $link, $comment, etc) being edited.
Since they are using it on a settings page, they don't have an object to edit so they didn't pass a second parameter. If they are going to use this hook, they should include a second parameter, even if it's a blank one, so everyone else who uses the hook will not get errors.
Like I said, I could be mistaken and perhaps it is all my fault but I'm pretty sure this is an All-In-One issue.