Eanable mode-rewrite on Apache

Enable mod-rewrite:

sudo a2enmod rewrite

Edit file /etc/apache2/sites-enabled/000-default and change AllowOverride None to AllowOverride All

sudo nano /etc/apache2/sites-enabled/000-default

Before:

Options Indexes FollowSymLinks MultiViews
AllowOverride None
Order allow, deny
allow from all

After:

Options Indexes FollowSymLinks MultiViews
AllowOverride All
Order allow, deny
allow from all

Now restart apache:

sudo /etc/init.d/apache2 restart

Resources: http://www.ubuntu-for-humans.blogspot.com/2009/11/enable-mode-rewrite-on-apache-ubuntu.html