JeffreyPia on "[Plugin: WordPress SEO by Yoast] Fatal error after plugin activation"

Upon plugin activation, the site front-end returns the following error:
Fatal error: Call to undefined method WP_Query::is_main_query() in /wp-content/plugins/wordpress-seo/frontend/class-frontend.php on line 431

http://wordpress.org/extend/plugins/wordpress-seo/