I do not run an anti virus application.
Are you sure you don't run an anti-spyware ? It's the same problem.
Have you been ASKED permission to run the two modules when you first ran FSX after installing the scenery ?
Have you replied YES to both questions ?
If not, check you haven't mistakenly put "virtuali" in the non-trusted authors: this will prevent ANYTHING signed by us to run.
To verify this, you can go to the Control Panel, under "Internet Options", look for the "Content" tab, there should be an "Authors" button, that will list the software authors that you trusted, and another tab with untrusted authors. If you see "Virtuali s.a.s", remove it from both tabs (especially if it's under untrusted)
After doing this, REDO ALL the above Uninstall/Reinstall procedure (except the antivirus part, if you are REALLY not using an antivirus), and note if you are being ASKED permission to run the two modules when you first ran FSX after installing the scenery, and reply YES to both question.