So with some more searching and more reading, I understand it's not called a Header, it's a "navbar". Sorry.
I have resolved my problem, but can someone please tell me if this will have a negative effect, or if I handled this the wrong way.
I removed the following line from /arcade/functions/functions.php (line 1261):
Code:
eval('$navbar="' . fetch_template('navbar') . '";');
It now looks as it should.