I've just see a youtube video about someone that installs 10.7.1 and I see that when the instalation:
Finish you have to get this screen:
But my laptop suddenly reboot itselfs when it's one minute to go (I tought I was right, but now I'm not that sure).
Am I right??
Bad image i believe buddy.
Get a copy of iatkosl2 (If you already own a copy of lion legally it shouldn't be an issue with forum rules to ask this).
Burn it on a standard dvd at 4x speeds and use that.
Playing around with the usb style installations can cause issues.