For some unknown reason, 3Com will not provide this driver on their site because of some bundle with Microsoft's HomeClick network setup wizard (which is just a friendly front end that manipulates your network settings).
The drivers were just sitting in a folder named \drivers on that CD.
I happened to install this adapter on a legacy free system (no CD, no floppy) and I figured I could download the driver from the 3Com website.
Shame on you 3Com! I though I could count on your products over the lesser brand names.