fatal-error

wp() is quite essential function. It resides in functions.php file (don’t confuse with functions.php in theme, different thing) and I don’t think you can load WP without passing require directive for that file at some point. So your install seems very broken – either functions.php file in core is damaged or something else is broken … Read more

There is a bug in WordPress 3.3.1 causing the issue. It may affect other versions as well. To solve the issue you can update WordPress to the current stable release and do integration testing afterwards. Or you can do a quick bug fix. To fix the bug: Open file blog/wp-admin/includes/screen.php in your favorite text editor. … Read more