I have a classic ASP page - written in JScript - that's using Scripting.FileSystemObject to save files to a network share - and it's not working. ("Permission denied")

The ASP page is running under IIS using Windows authentication, with impersonation enabled.

If I run the following block of code locally via CScript.exe:

var objNet = new ActiveXObject("WScript.Network");
WScript.Echo(objNet.ComputerName);
WScript.Echo(objNet.UserName);
WScript.Echo(objNet.UserDomain);

var fso = new ActiveXObject("Scripting.FileSystemObject");
var path = "\\\\myserver\\my_share\\some_path";
if (fso.FolderExists(path)) {
    WScript.Echo("Yes");
} else {
    WScript.Echo("No");
}

I get the (expected) output:

MY_COMPUTER
dylan.beattie
MYDOMAIN
Yes

If I run the same code as part of a .ASP page, substituting Response.Write for WScript.Echo I get this output:

MY_COMPUTER
dylan.beattie
MYDOMAIN
No

Now - my understanding is that the WScript.Network object will retrieve the current security credentials of the thread that's actually running the code. If this is correct - then why is the same user, on the same domain, getting different results from CScript.exe vs ASP? If my ASP code is running as dylan.beattie, then why can't I see the network share? And if it's not running as dylan.beattie, why does WScript.Network think it is?