nextgen galery

It wont allow me to add images and i get the following error when i try to add a gallery to a page:

Fatal error: Call to undefined function get_current_screen() in /homepages/24/d473658175/htdocs/gavick/gk_steakhouse_quickstart_WP_40/wp-includes/admin-bar.php on line 486

Hello,

Please check also the default theme, like Twenty Thirteen and let me know if the problem is only in the Steakhouse theme.