Hello All,
I know that this is a very old problem, and I also know that it has been discussed a lot, but I am really confused with clean URLs. I have setup Drupal 6.22 on Debian Squeeze and I have enabled mod_rewrite using a2enmod. Below is what I have configured as a virtual host serving by Apache:

<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/pmo
        <Directory />
                Options FollowSymLinks
                AllowOverride All
        </Directory>
        <Directory /var/www/pmo>
                Options Indexes FollowSymLinks MultiViews
                RewriteEngine On
                AllowOverride All
                Order allow,deny
                allow from all
        </Directory>
       ErrorLog ${APACHE_LOG_DIR}/error.log
       LogLevel warn
       CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

Also, there exists a .htaccess file in /var/www/pmo in which RewriteBase is set to /pmo. Are these ok?
I am no able to setup clean URLs with the above configurations. Can anyone help?

Warm Regards,
Ali Majdzadeh Kohbanani