I’m not the first to be frustrated by the Popup Domination Plugin busting the WordPress admin after upgrading to 3.3. The reason for the break is pretty simple. The plugin uses a WordPress function that itself relies on a function that has yet to be bootstrapped at the point at which the plugin is loaded. The solution is easy thanks to this post. Once you apply the fix you’ll see that Popup Domination has an update. Just auto-upgrade to the new version and you’ll be fine.