I’ve been fighting with this problem for a couple of hours, thinking that I somehow botched the move of one of my sites. It seemed strange, as I was able to successfully move it from my local server, then to a staging server without any trouble!
Turns out that the problem is that I am moving from a Linux server to a Windows Web Hosting server where rivers flow uphill.
Solution: Remove the “./”
require('./wp-blog-header.php');
Becomes
require('wp-blog-header.php');
