I have had reports of WebDAV Navigator working without problems on the following servers:

Supported Servers

• IIS 6 & 7 on Windows 2003, 2008 and 7 Ultimate
• Apache 2 on OSX, Solaris and Linux
• PyWebDAV
• Novell NetStorage
• Synology DS409 and DS1010+
• Netgear ReadyNAS Duo
• MobileMe iDisk
• GMX MediaCenter
• Smartvault
• Airstash
• Box.net
• PowerFolder
• SwissDisk
• icloud
• dropdav.com
• Social data bridge (Connect to Facebook data)
• Milton WebDAV API for Java
• STRATO HiDrive
• Fabasoft Folio Cloud
• myDrive

Let me know if it works on your WebDAV server and I'll include them in the list, or fix any problems preventing it from working