Windows 2000 DAV client worked really well but as soon as XP came along it stopped working. It’s one of the more annoying aspects of XP, but having fought it a few times and tried all sorts of workarounds, I finally found http://www.hss.caltech.edu/help/unix/admin/web/apache-webdav-xp. Following what’s there has gotten it working again for customers. How long it will continue to work is anyones guess.