OK, so I am/was having this same issue too. I tried running as administrator when I right-clicked on the shortcut and it didn't work. I then right-clicked and went to properties. In properties I choose the Shortcut Tab and went to Adanced and checked the "Run as administrator" option to allow the shortcut to be run as admin and I also went to the Compatibility tab and checked the box "run this program in compatibility mode for" and it had a ddl, I chose Windows XP Service Pack 2. I also checked the box labeled "Run this program as an administrator" under privilege level.
As of right now it has solved the problem w/o any rebooting. If this changes I will post. I suggest trying these options if you are having this same problem.
Hope it works!
p.s. - I did not do anything w/ the DMZ settings.