So I guess I've got a bad USB hub... Do you know of any diagnostic tools for such a thing?

Yes. Buy a new USB hub of a different brand. USB hubs are a dime a dozen.

So, if you have any simple suggestions for getting that to work I would appreciate it.

Most of the suggestions are in the network troubleshooting steps in the FAQ.

Did you try plugging it directly into the computer with a crossover cable? Do you have more than one computer to try that with? i.e., narrow down whether it's the computer, the wiring, the hub, the card, the settings, etc.