Use Apache Rewrite and htaccess to get Apache rewrite to work and make your urls pretty on Ubuntu. Lets assume that your website root directory is located in /var/www/headstation. Say you want to make this url:
In the website root doc directory, add a .htaccess file with following content:
RewriteEngine On RewriteBase /headstation/website/ RewriteRule ^wiki/(.*)/?$ wiki.php?tag=$1 [NC,L]
Check the /etc/apache2/sites-available/
Options FollowSymLinks AllowOverride None
Make sure that Multiviews is not in the lines above. Thats it!