RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-l
RewriteRule .* index.php [L,QSA]

Options -Indexes
ErrorDocument 403 /errorpages/403.php
ErrorDocument 404 /errorpages/404.php