These drivers were intended as an upgrade from version 1.2 to 1.4. I modified the original file, V14A.exe, to make it easier to use as a full installation also.
For a full installation the modem MUST show in device manager as a 'PCI serial controller'. On first boot up after installing it you'll get the 'new hardware found' box. Keep hitting 'next' and it'll eventually finish and say it couldn't install any drivers. That will force it to show in device manager correctly as the PCI serial controller. If you've attempted previous installations that haven't worked you may need to go to add/remove programs and remove them.
MDM28PSVD.exe is a self-extracting