I have a regex expression in my .htaccess. Took me ages to finally get it going. What I'm trying to do is grab anything after the domain and if there is a valid file display it, otherwise handle the URL for a vanity URL. The problem is it only works case sensitive so if there if default.html and Default.html are used for example one. I've tried fooling with it for days and all I've gotten is 500 errors. Maybe someone sees something I'm doing wrong here, still new to regex and the .htaccess.
Options +FollowSymLinks
RewriteEngine On
RewriteCond %{SCRIPT_FILENAME} !-d
RewriteCond %{SCRIPT_FILENAME} !-f
RewriteRule ^(.*) /URLHandler.php [NC,L]