Try this (you can paste this into a text document and give it a name that ends in '.vbs'). It will run under cscript.exe or wscript.exe and creates a file 'Users.txt' on your c: drive with the names of your users. <admin-user> is the signon of an admin user and <password> is the password for that admin user:
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' SysGrunt, 02/23/2004
set objAuthApp = CreateObject("Authenticator2.Application"

set objAuthDoc = objAuthApp.Documents.OpenWithBasicSignon _("default", "<admin-user>", "<password>"
Set fso = CreateObject("Scripting.FileSystemObject"
Set ts = fs

penTextFile("c:\Users.txt", 2, 1)
' gets users for each UserFolder
Set objOne = objAuthDoc.UserFolder
Set objTwo = objOne.Users
For each person in objTwo
ts.WriteLine person
Next
ts.Close
Set fso = Nothing
set objAuthDoc = Nothing
set objAuthApp = Nothing
wscript.echo "Done!"
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You will have to have AccessAdmAuto.exe on the box you run this from, and the default namespace must be the namespace you wish to query.