The point of that was to remove all the books. That was suppose to happen. Not sure why it won't download. I've this several times and never had any trouble downloading. Are you sure you only erased the 1 file? If you erased other files, that could explain the problem. If that is the case, try a factory reset. Otherwise you will need to reinstall the update manually.
BTW, the rest button on the back does nothing but force the device to turn off, sort of like rebooting a computer. If there is an inherit error on the device, this won't fix it.