I get an 500 .htacces error when I use this in my .htaccess file:
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*/([a-zA-Z0-9_-]+)|([a-zA-Z0-9_-]+))$ ./profile.php?username=$1 [L]
I type this without any other lines. Whats the problem and solution? Please help.