Insufficient Permissions

Is this a server error or a WordPress error? Sounds like the later to me and if so it isn’t a real admin user, like something has been corrupted. Is there another user who can reset yours? Can you create another admin user and use that the reset the permissions on the first?

Also: http://www.google.com/search?q=You+do+not+have+sufficient+permissions+to+access+this+page.

Then look through those Google results. There may be a solution for you in there. And try what I suggested if you can.