Please don't post new questions into existing threads.
Nothing "above" your document root (public_html or www) is accessible via HTTP; you need to use the filesystem on the server. (On a general note, including
anything local via URIs is a bad idea; it invokes an unnecessary loop-back and will probably return the results of running the file, assuming that the file has a .php extension. Oh, and it's usually a good idea to use
require or
require_once rather than
include for something upon which the rest of the page depends. If an include goes missing, you won't notice until you try to use it, which can result in some pretty nasty and confusing error messages going out to the user (or quickly filling your error log file). When a require goes missing, you get an immediate error telling you exacctly what the problem is.)
Your document root (/home/webjusti/public_html) is accessible using $_SERVER['DOCUMENT_ROOT']. To get from there to your user home directory, use the dot-dot directory, then work downward from there if needed. So:
PHP:
require_once $_SERVER['DOCUMENT_ROOT'] . '/../wp-config.php';