Michel,
Fortunately it turns out to be an easier situation than that. One of my kids decided they needed to free up a port on the router, so they unplugged the ISY.
Not sure why they didn't bother to simply connect to the Cisco hub that is right there with 4 empty ports. They probably just went for the first thing they saw, which was the Apple Airport Extreme Basestation ... and sense that worked, well, they were finished.
I've barely scratched the surface of what can be done with this unit. I switched to it mostly do to poor experience with the SmartHome software and not wanting to have to run it off a PC.
It works so well, I have needed to connect to it for anything in quite a while until last night when I wanted to make a small adjustment in one of my scenes.
Kudos on what seems to be a rock solid reliable product; though it's not kid tamper proof!