500 Internal Server Error

To create my network, i’ve upload .htaccess file into the root folder of wp (that is the same of my site: /).

The content of this file is:

—
RewriteEngine On
RewriteBase /
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]
—

But with this file the site is not reachable and show the 500 error.
I can only solve the problem by renaming or deleting .htaccess, but in doing so I can not access other blogs created (that I think they need of .htaccess)

ps: on my server mod_rewrite is enabled by default

Sorry for my English
Thanks