Hi from a begginer user of CI

[eluser]Zorancho[/eluser]
Hi all, i just started coding with CI after mucking around with CakePHP, so i found CI much easier to use and extend it in a flexible way.
So, this is my problem:
I have my website on http://localhost:8888/website and using .htaccess file like this:
RewriteEngine on
RewriteCond $1 !^(index\.php|images|js|css|robots\.txt)
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L,QSA]

I don't know what it really does, but it works for me. The only problem is that i have this kind of file structure: website folder is in www folder of the wamp directory and inside the website folder i have: system, images, css, js folders and .htaccess file from above.
When i go to an url in my address bar: http://localhost:8888/website/css i can get to the css file or to the images folder and js folder as well. How i can prevent direct access to those folders? I have been advised to use modification in httpd.conf file of apache, but some say that i should change the .htaccess file. I want to protect those folders since i am using the images folder for getting images for registered users on my website. And if i go to website/system i get message: Directory access is forbidden. How can i change this to when a user tries url that doesn't exist to be redirected to some existing site like the home site instead showing that error message?
Thanks in advance.
Zoran