Mounting Via WebDAV From Windows

As of Windows XP the Microsoft Filesystem Redirector, by default, only supports DIGEST authentication.  To utilize a WebDAV server using BASIC authentication the support has to be enabled via a registry key.  The WebDAV client is configured via keys in the system hive at "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters".  Create a DWORD key named "UseBasicAuth" with a value of 0, 1, or 2.

• 0 - Basic authentication disabled, this is equivalent to the default if the UseBasicAuth key is not  set.
• 1 - Basic authentication is allowed for WebDAV provided that the connection is protected by SSL/TLS.
• 2 - Basic authentication is allowed for WebDAV regardless if the connection is protected.

 A value of "1" is recommended for any type of production network;  for debugging and development purporses "2" is useful as unprotected connection can be watched with any packet capture tool such as WireShark.  Only allow unprotected connections if you are comfortable with them being seen by any third party [seeing includes both the username and password].  Attempting to mount a volume from a server using BASIC authentication that does not match the requirements set by "UseBasicAuth" will generally result in a "System Error 67".
Regardless of how user enters their credentials when prompted Windows will send a username qualified by the NetBIOS domain of either the current machine or the current domain.  If your OpenGroupware Coils server does not use an authentication scheme where qualified names are recognized you can set the StripAuthenticationDomain server default;  with that default enabled the server still strip the NetBIOS domain from the from the beginning of any login credentials before authentication is attempted.  However that operation also means that any usernames containing a "\" character will fail to authenticate.

coils-server-config --directive=StripAuthenticationDomain --value=YES

Mounting OpenGroupware Coils as drive X:

Typically if your attempts to authenticate fail with a Windows "System Error 5 has occurred" it related to sending qualified usernames to a server that expects unqualified usernames.
With BASIC authentication enabled and automatically unqualifying usernames it should be possible to mount your OpenGroupware Coils' WebDAV presentation on a Windows Workstation.
More technical information for either using the Microsoft Windows Filesystem Redirector or OpenGroupware Coils authentication options can be found at the Wiki of the SourceForge project.