Accessing Files On Another Server

Development environment: Windows 2003 Server running IIS6 and the same
server running as a domain controller, DNS and DHCP servers.

Production environment: Windows 2000 Server SP4 running IIS5 and not used
to provide domain control or name services.

The two environments are on different networks with no trust relationship
between them. In both environments the web server is set up to disallow
anonymous access and to use integrated Windows authentication. The
application is vanilla ASP (i.e. not .NET) VBScript.

In the development environment, the following code runs flawlessly no
matter whether "myUNCPath" points to a share on the web server or a share
on another server in the same domain.

Set objFilesys = Server.CreateObject("Scripting.FileSystemObject")
If Not objFileSys.FolderExists(myUNCPath) Then
Set objFolder = objFileSys.CreateFolder(myUNCPath)
End If

However, in the production environment it falls over with a permission
denied error when "myUNCPath" is on another server and further testing
shows that the FolderExists method is returning false even when
"myUNCPath" exists. The network share is configured to give full control
to the Everyone group.

I've found http://support.microsoft.com/kb/207671 which although
referring to IIS4 suggests that the issue could be the authentication
method (I'm assuming that integrated Windows authentication is close
enough to NT Challenge/Response and so might generate a token that cannot
access network resources). I'm not sure of this is the problem because if
it were then the code shouldn't work in my development environment.

Any ideas on what's going wrong and how to access the network resources
in the production environemt?