MultiSite

Trying out multisite locally; I run in some problems.
As soon as I add the .htaccess with:

RewriteEngine On
RewriteBase /web/DEV.wp3.ch/
RewriteRule ^index\.php$ - [L]

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) $2 [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

I get an error 500 all the time. When I remove (or rename) the .htaccess file, then tha admin works fine but of course the links to the “subside-folders” lead to an error 404 then.

I’m on an Ubuntu notebook with XAMPP and having my webs in my home folder but really don’t remember how I linked it there….

Does anyone else have similar difficulties or a hint on wha’ts wrong here. Thank you!