Network Dashboard-Link misses a directory

Hi,
I created the ability for WP Multisites through the guide here on WP.org, for subdomains. After that I wanted to go to the dashboard for my new network to set it up but it couldn’t find the site and shows a 404.

But then I realised this is because it misses my directory folder where the wp installation is on my root. When I manually put the correct directory in it works.

path actually is “root/wordpress/wp-admin/network…
network dashboard and the other links want to go to “root/wp-admin/network…

How can I change this?
Live page is http://www.xn--gemischtette-mlb.de/
and I only wanted to create a subdomain for galleries here at galerien.xn--gemischtette-mlb.de/

.htaccess is this:

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^(.+) - [PT,L]
RewriteRule ^(.+) index.php
# BEGIN WordPress
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) wordpress/$1 [L]
RewriteRule ^(.*\.php)$ wordpress/$1 [L]
RewriteRule . index.php [L]

# END WordPress

Please help.