I recommend that if you are upgrading your database on a windows server you ensure that your config files (admin/includes/configure.php and includes/configure.php) are set to READ-ONLY (as they should be inb normal use anyway).

You can safely ignore the warning message that comes up during the upgrade/install process. The upgrade process doesn't require access to these files. But if you give it you risk your config settings being lost.

This is a PHP v windows problem.