Site lost after trying to upgrade wp

Hello,
today I tried to upgrade my wordpress installation.
When doing so I got stuck at “unpacking package”,

I read here that I should add the line:
AddType x-mapp-php5 .php
into the htaccess file and so I did.

Now when I try to load the website on firefox I got a blank screen and when I try to load the website on chrome I see this:

<?php
/**
 * Front to the WordPress application. This file doesn't do anything, but loads
 * wp-blog-header.php which does and tells WordPress to load the theme.
 *
 * @package WordPress
 */

/**
 * Tells WordPress to load the WordPress theme and output it.
 *
 * @var bool
 */
define('WP_USE_THEMES', true);

/** Loads the WordPress Environment and Template */
require( dirname( __FILE__ ) . '/wp-blog-header.php' );

What happened exactly and how can it be fixed?