Mod_rewrite and Furls

[Michal Mroz]

Hello. I'd like to enable friendly urls, but i already have a .htaccess. which runs important rules for my external website. Combining it doesn't work. My current code:
 

Options +FollowSymlinks
RewriteEngine On
RewriteBase /

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

RewriteRule ^([a-z0-9\_\-]+)\/([a-z0-9\_\-]+)/?$ index.php?action=$1&sub1=$2 [NC,L]
RewriteRule ^([a-z0-9\_\-]+)/?$ index.php?action=$1 [NC,L]

I made it to work for the whole website and forums except ACP. Going to /admin/ ends with The page you requested does not exist. How can I make it to work?