If you are having difficulty using Windows 7 to connect to a Web-based application on an Apache/Linux-based WebDAV server, you may need to enable support for Basic Authentication for WebDAV on your Windows 7 computer. To do this, open Registry Editor and create the following new registry entry under HKLM\SYSTEM\CurrentControlSet\Services\WebClient\Parameters:
Type: DWORD (32-bit) Value
If you do this, you should make sure the Web-application uses SSL since the Basic Auth password is sent in cleartext.
Note that the possible values you can assign to this new registry entry are:
0 - Basic authentication disabled
1 - Basic authentication enabled for Secure Sockets Layer (SSL) shares only
2 or greater - Basic authentication enabled for SSL shares and for non-SSL shares