SEO by Yoast plugin error

Hi, yesterday I updated my SEO by Yoast plugin and it caused the following error:

Fatal error: Cannot redeclare yoast_breadcrumb() (previously declared in /home/movingto/public_html/directory/wp-content/plugins/wordpress-seo/inc/wpseo-functions.php:82) in /home/movingto/public_html/directory/wp-content/themes/cityguide/includes/theme-plugins.php on line 277

Today I’ve updated my theme to the latest version but I still have this error message – my whole site goes down.

Is this a plugin error or an error with my theme (cityguide)?