I was checking to make sure that you were not shutting short_open_tag off via .htaccess. At this point I can only conclude that one of the following must be true:
1. short_open_tag is not On in the right ini for XAMPP
2. or that XAMPP has a problem with the directive
3. or that you have not restarted XAMPP after changing the settings
4. or that PHP isn't working on your server
You may want to create a test.php in your web tree and browse to it. In the file put the following:
<?php phpinfo(); ?>
This should print out a list of how php is configured, and what extensions are enabled, etc.