I just had to post this since I spent the last 2.5 hours figuring this out on a work pc and every site I went to and every fix I tried nothing worked.

If there is any key under the below reg key that is not a number you'll get that error. I've reproduced it on 4 Win7 x64 Enterprise pc's and it broke every one of them. Hopefully someone struggling to find the answer like I was will stumble across this. I'm going to post it other places too to make it easier to find.

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\Zones

If you want to test, create a key like below and then try running appwiz.cpl from the command line.

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\Zones\a