Htaccess mistake plugin

The W3 Total Cache plugin add some rules to the .htaccess in the root of the WordPress site. This generates a internal server error. When i delete the .htaccess file and regerate it in the permalink section and empty the cache, the site is be working.

But a day later, the plugin adds again rules to to .htaccess and we get the same problem. So i look into the htaccess file and locate the problem here;

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress
        Header append Cache-Control "public"
         Header unset Set-Cookie
         Header set X-Powered-By "W3 Total Cache/0.9.4"
    </IfModule>
</FilesMatch>

You can see, the is something missing in the file. The if module and Filesmatch begin.

Full .htaccess file http://pastebin.com/TmU3uS0X

https://ww.wp.xz.cn/plugins/w3-total-cache/