Go into your menu and change it to without your permission, then turn off your 811 over night. (put into standby, don't unplug or cut power to 811, just press the power button on the front of the 811 or remote) If you want to see it, after you change it to without your permission you can put the 811 into standby mode without turning off your TV and it will after a minute or so bring up a downloading software screen and you can watch it download.
There really isn't any reason to have your 811 set to ask permission, other than keeping you from getting updates automatically. But if you want to keep it that way then you can go back in and change it back after the download is finished.
If your 811 still don't take the download after doing that then I don't know. Good Luck