The usual: your antivirus must have mistakenly blocked the new version. Some antivirus are so bugged they block "by default" any program that is new, just because it's new, they don't know it and it hasn't gained enough "reputation" to be considered safe. Which of course it's entirely wrong, since it prevents software from being updated.
- Configure the antivirus to exclude the whole Addon Manager folder
- Be sure your firewall is not blocking the updated.
- Run the FSDT Live Update again.