This error doesn't have anything to do with running under Adminstrator or having UAC off. Is the result of you mistakenly put us in the "Untrusted Publisher" list, so everything signed by us will not work. Not just the installers, but everything so, even if you managed to install, it won't run anyway. This can't happen without your manual intervention. Only you can un-trust a Publisher, and only you can re-trust it.
To fix this, go to the Control Panel, under "Internet Options", look for the "Content" tab, there should be a "Publishers" button, that will list the software publishers that you trusted, and another tab with untrusted publishers. If you see "Virtuali s.a.s", remove it from both tabs (especially if it's under untrusted)