Need help ASAP plz working on this large companies website and I can't figure this out.

[screadore]

Wordpress gave me the following error when uploading the this themeforest theme. 

failed opening '/srv/htdocs/wp-content/themes/QuickFixWebiste(Wordpress)/../../../wp-admin/includes/class-walker-nav-menu-edit.php' for inclusion (include_path='.:/usr/local/php7.2/lib/php') in /srv/htdocs/wp-content/themes/QuickFixWebiste(Wordpress)/library/core/admin/edit-menu-walker.php

Can anyone tell me how to resolve this?

The source code in the edit-menu-walker.php on lines 1-4 is:

<?php
if (!class_exists('Walker_Nav_Menu_Edit')){
	include_once(get_template_directory() . '/../../../wp-admin/includes/class-walker-nav-menu-edit.php');
}

 

[requinix]

Whatever you did or installed, you didn't get it right. You're missing at least that one file. Probably others.

[maxxd]

Use get_home_path().

require_once(get_home_path().'wp-admin/includes/class-walker-nav-menu-edit.php');