After executing your sample script "Printers.vbs" the new Printer "NewPDFCreator" still has the default profile assigned!
The problem is, that at this time
doesn't exist! The key is not created before following user interaction:
PDF Creator - PDF Print Monitor.Menu.Printer.Printers.SaveButton: Press.
Is there a workarraound (by COM interface) or are you going to fix it soon?