Wel, maybe before you head out the door to spend money, I can help you out.
First, I want to know HOW you are programming your scene triggers. The problem could be as simple as "you're doing it wrong". It wouldn't be a first time a user has had this problem.
Regarding USB Hubs:
I had my three Korg nano devices plugged into a powered USB hub, and all were recognized and functioning properly. Using MIDIOX, it saw them. Using them with Sonar Home Studio 6, it again saw them. I even plugged in the MyDMX hardware into the USB hub and the OS recognized it. It had to re-install the driver to the port, but that's nothing I worry about. While MyDMX came up, it didn't work so well, so I exited and relaunched with the same results. I quit MyDMX, plugged the dongle directly into a USB port, launched MyDMX and it ran fine but it would NOT recognize any of the nano units.
Since MIDIOX says it works, it appears there's no reason to run out and buy a cable or anything.
So, please describe your method for programming triggers. MyDMX will NOT work with a keyboard until you've programmed the scene triggers AND MyDMX MUST be the foreground application..
You're doing everything else right. You're going keyboard to MIDI interface to USB on laptop, MIDIOX sees it. I think you're maybe not doing your trigger programming properly.