I'm sorry, but I cannot reproduce the problem:
- Restart Windows
- Be ABSOLUTELY sure you have added the whole Addon Manager folder to the antivirus Exclusion
- Be ABSOLUTELY sure your firewall is not blocking the Live Updater.
- Try the Live Update again, after a Windows restart.
If still doesn't work, manually delete all the following files from the Addon Manager\Couatl folder:
Qlmlicenselib.dll
Qlmlicenselib.dll.manifest
QlmLicenseWizard.exe
and run the FSDT Live Update again.