If you can't even ping the device then there is a more serious issue.
Regardless of whether the server runs SMB, AFP, NFS or any other protocol you should still be able to ping it.
Either it's some sort of network issue between the computer and the NAS, or you have a deeper problem in your network stack, or below the top layer.
I would suggest uninstalling and reinstalling the IP stack and attempting the ping again.
Any 64 bit vista machine i've used with this device is at a minimum able to ping it.
This makes it seem as if this isn't a compatiblity issue per se, it's something particular to your environment here.
If the machine is pingable from other computers on your there's nothing else to modify on the NAS to change this situation on the 64 bit machine.
Failing that, try to boot into safe mode w/networking and try pinging/connecting by UNC path.
If that doesn't work, try a system restore or a complete reinstall of windows.