Windows comes with builtin support for WebDAV. You can mount a WebDAV server like a file system and access it through the Explorer and via a drive letter. On the start menu, select “Computer” where you find “Map network drive” in the toolbar.
In the connection dialog, enter the server address and chose “Connect using different credentials”.
Enter your email address and password, like you use when logging on to autorouter.eu. Now you should see a folder in Explorer that shows the contents of the autorouter AIP WebDAV server.