The issue doesn't have anything to do with the addon manager or couatl, they are not the cause of the problem, but it's something in your system that is *affecting* them.
N.1 likely cause it's the antivirus or a firewall, either it has blocked the download of the updated version, or it's corrupting the file when it's being run.
Of course, it would be easier to diagnose the problem in your system which is affecting the two modules, if you were more precise in your description. What do you mean with "FSX does not run ", exactly ?
Does FSX starts then it quits to desktop without any messages ? If Yes, this is 100% sure an antivirus/firewall problem.
Does FSX starts with an error message ? If yes, which one ?