@ClaytonJames all of them links you have there are for older version of WP, and don't help out any since this is a WP 2.7 feature that's not working.
I see. Actually, file and folder permissions, as well as file and folder ownership issues, apply no matter what version of WordPress you use. My point was, there is a lot of conversation in the forums concerning the use of automatic upgrade and how it might be responsible for adversely affecting file and folder permissions or ownership, and what others affected by this issue have done about it.
More specifically, I gave those references because of the title of this thread;
"You do not have sufficient permissions to access this page"
That makes it (in my opinion), in all probability, a file/folder ownership permission issue. How could permission or ownership values change if you didn't change them? Possibly by allowing a plugin or script to access the network and write to your directories.
I've sett all my directory permissions to 777 to see if it was a file permissions problem,
You have set your directory permissions to check a suspected file permission problem.
My thinking could be off a bit off on this, (it's Happy Hour here!), but just because you set a directory to 777, doesn't mean the files inside are 777 unless you set the permissions intentionally recursive, (which would not be wise) or that an ownership issue on a file still won't give you a problem. But there could be other reasons you are having the issue. Might be something as simple as file corruption or incomplete upgrade.
I may be in error by making the somewhat broad assumption that you all may have used an "automatic upgrade" feature at some point prior to this issue. If so... carry on. Good luck to you.