Internal Server Error with WordPress theme on Windows Server

I found a WordPress theme that I really liked at http://www.webdesignlessons.com but when I activate the theme in my WordPress 3.0.1 installation on Windows Server 2008 R2 I’ve got the dreadful Internal Server Error. Installed the theme on my Linux box and everything worked fine! Hmm … a Windows Server problem.  Since I don’t give up easily I started looking around in the php files even though I’m not a php person. After a while I located the problem. The endif statement in the WordPress theme!!!  endif was written in the following way in a few places.

<? endif; ?>

If I changed this into

<?php endif; ?>

Everything worked as expected.