If your server is set with both FollowSymLinks and SymLinksIfOwnerMatch off, then rewrite rules will stop working, and cause a 403 forbidden error message. You’ll also see something like this in your apache error log.
[rewrite:error] [pid 19455] [client 127.0.0.1:55311] AH00670: Options FollowSymLinks and SymLinksIfOwnerMatch are both off, so the RewriteRule directive is also forbidden due to its similar ability to circumvent directory restrictions : /home/username/public_html/favicon.ico, referer: http://www.domain.com/ : /home/username/public_html/403.shtml
If you wish to enable this for a particular folder, simply add this to the .htaccess
Your rewrite rules should no longer break your site once this has been added.