ROFL, that command should have given a long stream of output - if I had known it was that short I wouldn't have suggested the paste bin!
Now, your problem is beginning to get me outside my comfort zone, but that is always interesting, so here goes.
Click on the Start menu and in the start box type 'services.msc' (without the quotes of course) to run that program. It will probably ask you to click again to confirm you want to do that.
After a while, a list of services that are running on your computer will come up. This makes for interesting reading (for a geek), but the one we are interested in is 'DNS Client'. That should have a status of 'Started', but I bet it is not showing that on your PC.
Make sure the 'Extended' tab at the bottom is selected, click on 'DNS Client' and then click 'Start'. If it was already started, click 'Restart' for luck.
Now that has sorted why you couldn't display the cache or reset it, but I don't think that will have sorted the AVG problem. You could try a reboot now, but I still think uninstalling and reinstalling it is the way to go there.
If the DNS Client wasn't started, your hosts file will have been ignored anyway, so don't bother posting it .