Fatal error message when editing a theme

So I am trying to edit a theme. But I just get this fatal error message, I can edit the Humean theme because it’s active but I can’t edit any other theme :/
If any dev of the theme needs to login and try I will gladly create a administrator account for you.

Fatal error: Uncaught Error: Class ‘HA_Customize_Header_Image_Data_Setting’ not found in /home/linus/blog/wp-content/plugins/hueman-addons/addons/skop/czr-skop.php:2333 Stack trace: #0 /home/linus/blog/wp-includes/class-wp-hook.php(298): HA_Skop_Cust_Register->ha_alter_wp_customizer_settings(Object(WP_Customize_Manager)) #1 /home/linus/blog/wp-includes/class-wp-hook.php(323): WP_Hook->apply_filters(NULL, Array) #2 /home/linus/blog/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #3 /home/linus/blog/wp-includes/class-wp-customize-manager.php(754): do_action(‘customize_regis…’, Object(WP_Customize_Manager)) #4 /home/linus/blog/wp-includes/class-wp-hook.php(298): WP_Customize_Manager->wp_loaded(”) #5 /home/linus/blog/wp-includes/class-wp-hook.php(323): WP_Hook->apply_filters(NULL, Array) #6 /home/linus/blog/wp-includes/plugin.php(453): WP_Hook->do_action(Array) #7 /home/linus/blog/wp-settings.php(469): do_action(‘wp_loaded’) #8 /home/linus/blog/wp-config.php(94): require_once(‘/home/linus/blo…’) #9 /home/linus/blo in /home/linus/blog/wp-content/plugins/hueman-addons/addons/skop/czr-skop.php on line 2333

The page I need help with: [log in to see the link]