Problem: Upgrading WordPress to 2.8.1 and above -> Missing permissions?

As I recently upgraded my WordPress version to v2.9.1, I faced the problem, that the administrative pages of some of my beloved plugins don’t work any more. The message you get displayed is “You do not have sufficient permissions to access this page.“. I found out that this is because of a modified security mechanism in WordPress version 2.8.1 and above. If your plugin provider doesn’t maintain your plugin any more, this article provides information for easily fixing this problem yourself.

The quickfix

Check your plugins .php-files for a fragment called …

add_action('admin_head', ...

and replace admin_head with admin_menu.

That’s it. For me, this fix has worked fine for each of my used plugins (Adsense Deluxe, Widgetize Anything…).