Fatal Error when Metabox installed

Hello I have noticed an warning + error when metabox activated.

Warning: require(/www/doc/www.digiamo.cz/www/napresno/wp-includes/SimplePie/Parse/Date.php): Failed to open stream: No such file or directory in /www/doc/www.digiamo.cz/www/napresno/wp-includes/class-simplepie.php on line 16

Fatal error: Uncaught Error: Failed opening required '/www/doc/www.digiamo.cz/www/napresno/wp-includes/SimplePie/Parse/Date.php' (include_path='.:/usr/share/php') in /www/doc/www.digiamo.cz/www/napresno/wp-includes/class-simplepie.php:16 Stack trace: #0 /www/doc/www.digiamo.cz/www/napresno/wp-includes/feed.php(789): require_once() #1 /www/doc/www.digiamo.cz/www/napresno/wp-includes/widgets.php(1571): fetch_feed('http://feeds.fe...') #2 /www/doc/www.digiamo.cz/www/napresno/wp-admin/includes/dashboard.php(1585): wp_widget_rss_output('http://feeds.fe...', Array) #3 /www/doc/www.digiamo.cz/www/napresno/wp-content/plugins/meta-box/inc/about/dashboard.php(63): wp_dashboard_primary_output('dashboard_prima...', Array) #4 /www/doc/www.digiamo.cz/www/napresno/wp-content/plugins/meta-box/inc/about/dashboard.php(41): RWMB_Dashboard->get_html() #5 /www/doc/www.digiamo.cz/www/napresno/wp-includes/class-wp-hook.php(309): RWMB_Dashboard->add_news(false) #6 /www/doc/www.digiamo.cz/www/napresno/wp-includes/plugin.php(191): WP_Hook->apply_filters(false, Array) #7 /www/doc/www.digiamo.cz/www/napresno/wp-includes/option.php(886): apply_filters('transient_dash_...', false, 'dash_v2_6a99407...') #8 /www/doc/www.digiamo.cz/www/napresno/wp-admin/includes/dashboard.php(1156): get_transient('dash_v2_6a99407...') #9 /www/doc/www.digiamo.cz/www/napresno/wp-admin/includes/dashboard.php(1569): wp_dashboard_cached_rss_widget('dashboard_prima...', 'wp_dashboard_pr...', Array) #10 /www/doc/www.digiamo.cz/www/napresno/wp-admin/includes/dashboard.php(1275): wp_dashboard_primary() #11 /www/doc/www.digiamo.cz/www/napresno/wp-admin/includes/template.php(1401): wp_dashboard_events_news('', Array) #12 /www/doc/www.digiamo.cz/www/napresno/wp-admin/includes/dashboard.php(268): do_meta_boxes(Object(WP_Screen), 'side', '') #13 /www/doc/www.digiamo.cz/www/napresno/wp-admin/index.php(203): wp_dashboard() #14 {main} thrown in /www/doc/www.digiamo.cz/www/napresno/wp-includes/class-simplepie.php on line 16

Could you help me out?