If you had to enable mod_rewrite then chances are, your default apache setup will also need to be changed to allow the .htaccess to execute correctly. By default, most .htaccess rules in publicly accessible directories will be denied.
Depending on your setup you should have something like this ...
<Directory /var/www/> Options Indexes FollowSymLinks MultiViews AllowOverride None Order deny,allow deny from all </Directory>
Found in your config directory for a apache, which may be something like
Note that the path above and also the /var/www/ path in your Directory tag above, may be different.
You will need to change a few things, such as AllowOveride and also a few others to match below. Inspect for the differences.
<Directory /var/www/> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory>
Once you have changed that, restart apache and hopefully you will see that the rules in your .htaccess file are now executing.