USB Ethernet Problems With New MacBook Air?

I just bought myself a brand new MacBook Air, with a 128GB flash drive and the faster graphics. It runs much faster than the first-gen one I have and also runs much cooler, so in general I’m a happy guy.

But twice now, I’ve hooked up the ethernet dongle and plugged it into a network cable/port that I know works, and the adapter does not recognize that the cable is plugged in, and nothing I do (restart, unplug/replug) seems to help.

Has this happened to anyone else? I’ve tried it with two different dongles too, and the problem happened with both of them. Can anyone out there help?