Error Message While Accesing Network Admin

Hello,
Ive recently attempted setting up MultiSite within WordPress, but with little success.

Ive followed instructions exactly on how to set it up, and i now have the “My Sites” dropdown while on my dashboard. When i go to any page within my network admin, im faced with this error;

Fatal error: Call to undefined function get_current_screen() in /home/themin17/public_html/wp-admin/network/settings.php on line 22

I have taken off multisite, and then put it back on to assure i have followed instructions correctly.

Any help regarding the issues im having are deeply appreciated.

http://www.theminiplanetvoice.com