Hello again
If you are use codeIgniter so you have noticeed that the defalut URL contain index.php , maybe this annouiing you to remove it just follow these pages :
http://www.anmsaiful.net/blog/php/remove-codeigniter-index-php.html/comment-page-1#comments
and
http://linuxmoz.com/enable-mod_rewrite-on-ubuntu/
thats all
enjoy it