Receiving Invalid argument errors

I have a multisite setup, As soon as I network activate the plugin I receive the following error appearing on top of my word-press dashboard:

Warning: Invalid argument supplied for foreach() in /home/content/34/9983534/html/institute101/wp-content/plugins/wordpress-seo/inc/wpseo-functions.php on line 440

When I edit any seo settings and click save, I get redirected to a blank whit page with the error:

Warning: Cannot modify header information – headers already sent by (output started at /home/content/34/9983534/html/institute101/wp-content/plugins/wordpress-seo/inc/wpseo-functions.php:440) in /home/content/34/9983534/html/institute101/wp-includes/pluggable.php on line 875

Please help

http://ww.wp.xz.cn/plugins/wordpress-seo/