Theme breaks down when I rename plugins folder

Hi,

I am trying to figure out things that can be done to improve my theme installation. Godaddy found this and said this should be looked at:

When the plugins folder in wp-content is renamed the site throws up this error:
Fatal error: Call to undefined function vc_path_dir() in /home/********/public_html/wp-content/themes/mix/inc/vc/class/frontpageposts.php on line 2

Now the file frontpageposts.php is nothing but these code lines:
<?php
require_once vc_path_dir(‘SHORTCODES_DIR’, ‘vc-posts-grid.php’);
class WPBakeryShortCode_Wpo_Frontpageposts extends WPBakeryShortCode_VC_Posts_Grid {
}

Is there an easy fix to this? Pls note I am not a coder.

Thanks.