Templated printed twice

[eluser]Unknown[/eluser]
Hi all, for some reason my template in my project is displayed twice! I've been looking for the bug for a couple of hours now but I'm completely out of ideas!

I'd really appreciate if someone could have a look at it.

First of all this is what happens: http://www.ojii.ch/cibug.png

Now the more interesting part, code:

My controller: http://pastebin.com/m278a0d8e
My parser lib: http://pastebin.com/m418445e0


View files:

base.php: http://pastebin.com/m2a53c9fd
public/nav.php: http://pastebin.com/m25fb70de
public/main_page.php: http://pastebin.com/m422889c8

I know that's a lot of code but still, my whole page gets that bug and I just don't know why .

Please help a CodeIgniter Newbie!