Fix mod_rewrite erros in apache

change :

RewriteEngine On RewriteCond %{REQUEST_METHOD} ^TRACE RewriteRule .* – [F]

To this:

RewriteEngine On RewriteCond %{REQUEST_METHOD} ^TRACE RewriteRule .* – [F] RewriteLog /var/log/apache2/rewrite.log RewriteLogLevel 0

as described here