I had a similar problem a while ago, I think it’s due to something not being quite right in the database.
Has your host made any changes to the database or your wordpress installation? For that matter, have you?
Not that I know of. Do you have any idea how you fixed it?
Well, the way I fixed it might not be the way you want to go about it, since it was a white-knuckle ride from start to finish!
You might want to check out this solution first:
http://markjaquith.wordpress.com/2006/03/28/wordpress-error-you-do-not-have-sufficient-permissions-to-access-this-page/
But what I did was to make a backup of my database. You’ll need to use phpMyAdmin’s ‘Export’ utility to grab your database.
Then I deleted everything — and that’s the scary part. I got rid of all the files and the database itself.
I then re-installed wordpress as if it were a completely fresh install.
Then I re-imported the important tables back into my databse. So, from the fresh install, I emptied every table except for options, users and usermeta. Then, working with the exported backup from the old database, I re-filled each table with my old posts, comments, postmeta etc.
I’ve kept this deliberately brief so it’ll only make sense if you’re familiar with the wordpress database and phpMyAdmin — don’t attempt it if you’re not!
