If he had a file called autorun on his usb stick, then that is 1 of 2 things ... His usb stick has stuff on it that is set to run automatically as soon as he plugs it in to a pc (could be a sandisk with their portable utility, or he's using something like portableapps), or he has a virus on his usb stick, which is trying to automatically run...
Anyway, that wouldn't make any difference to the flashing of the vu, as it's all based on linux, not windows, so autorun and exe/com/bat files etc won't work on the box...
What I've noticed when flashing my solo, is that if I have a usb stick in the rear port, then it won't flash. I have to remove the usb from the rear of the solo, then plug my flashing usb to the front of the solo, and then update that way...