Sorry for the confusion.
I made a small mistake in my last post. I should have said, the following is what your index.php looks like (according to code you posted on github):
<php
session_start();
include("item.php");
?>
You are missing the ? in the first line. It should be:
<?php
session_start();
include("item.php");
?>
After I made the above change and used all the files you posted on github, the login portion works fine.