[Plugin: The Events Calendar] Event Category Fatal Error

I can’t see to figure out why this is happening but when the plugin is setup and activated I get a Fatal Error when going to the events category url mysite.com/category/events/

this is the error: Fatal error: Call to a member function get_var() on a non-object in /mnt/w1007/d27/s19/b02a4550/www/ykonline.ca/wp-content/themes/gazette/header.php on line 70
Any idea how to fix this?

http://wordpress.org/extend/plugins/the-events-calendar/