Hi Alain,
While I can honestly say I have no idea why there's the unknown device issue, I am happy to be able to explain why you're getting devices marked #2.
Windows is only intelligent enough to recognise that a device you have previously used is being plugged in, when you always plug it into the same USB port. If at any point you plug it into a different port, it sees it as a completely new device and puts a #2 next to it.
So, in short, so long as everything is working normally, the only thing you need to do to stop it installing several copies of the same device, is to always use the same port
I trust that helps.
Jon
eForum Team