I think USB drivers in general are written sloppily, maybe with a false sense of security re: the robustness of the protocol. If I ever have hardware problems, it's related to a USB device not getting along with others. Now, granted, everything's USB these days, so there's more chance of conflict. I have 10 devices at the moment...
I'm currently having a similar problem, though my mac doesn't even give me a warning, it just switches off, completely.
Running handbrake in the background converting mpg to mp4 with iPod-atom.
MBP connected to Dell screen-USB-hub with logitech wireless keyboard connector and iPhone.
MY handbrake always quits unexpectedly, and i have to start the stupid 12min conversion from avi to mp4 over again. Sometimes this happens more than 4times for just ONE file. It always happens when im multitasking or when im doing nothing and its minimized, however it has never unexpectedly quit on me when its the only thing running and im like physically watching it.
Very very very annoying. Seriously im starting to hate it each time it crashes.