I have the same problem. I installed MAB, activated it, but I don't have access to the settings.
The screen is like this: http://www.energie-de-vie.fr/wp-content/uploads/2014/02/MAB-screen.jpg
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When I click the Save changes button (without changing anything because I can't), the tabs are then displayed to their normal place, but the pages are still blank, all of them, including the Styles&Buttons pages, Add Button, etc...
The "Action boxes" work fine, but it's of no use since I cannot define the provider and the list it concerns.
I have the Mailchimp widget plugin installed. So I deactivated it to check if there is no conflict, but the problem remains.
I have MAB installed on other sites and it works just fine.
Thanks for your help.