Fatal error after updating to 3.5

Hi,

I updated wordpress to 3.5 and can no longer access the CMS. The website still works and I still have the login screen but after that I get the following error:

Fatal error: Call to undefined function get_taxonomies_for_attachments() in /websites/123reg/LinuxPackage21/ho/sp/it/hospitality-jobs-dubai.com/public_html/wordpress/wp-admin/menu.php on line 67

Website: https://www.hospitality-jobs-dubai.com

Any help would be massively appreciated. Thanks!