Betheme Theme conflict

Disable comments plugin conflicts with Betheme http://themeforest.net/item/betheme-responsive-multipurpose-wordpress-theme/7758048

[05-May-2016 18:40:36 UTC] PHP Notice: Undefined index: WP_Widget_Recent_Comments in /home/ourdomain/public_html/wp-content/themes/betheme/functions/theme-head.php on line 1176

Betheme code

if( ! function_exists( 'mfn_remove_recent_comments_style' ) )
{
	function mfn_remove_recent_comments_style() {
	    global $wp_widget_factory;
	    remove_action( 'wp_head', array( $wp_widget_factory->widgets['WP_Widget_Recent_Comments'], 'recent_comments_style' ) );
	}
}
add_action( 'widgets_init', 'mfn_remove_recent_comments_style' );

https://ww.wp.xz.cn/plugins/disable-comments/