mod_rewrite loop

[Walther Bauer <2313218@xxxxxxxxxxxxxx>]

This .htaccess snippet creates an "Request exceeded the limit of 10 internal redirects"-error on my server (XAMPP):

RewriteEngine On
RewriteRule ^(.*)$ ./server.php

while the following does not:

RewriteEngine On
RewriteRule ^(.*)$ server.php

So why does the "./" actually make a difference?
Thanks in advance.