Sorry I don't have that file, only the one named Couatl_Updater.exe in the Addon Manager folder.
Sorry, but that's not possible, you posted a screenshot with it displaying an error updating "GSX Scripts" and the only program that ever contains that message and does that step IS Couatl_updater2.exe
So, you surely must have it, at least when you saw that error, and it was likely an outdated version which was going to be downloaded by the first step of the update (the Couatl_updater.exe *DOWNLOADS* the current Couatl_updater2.exe, which does the real job )
If you are *really* sure Couatl_updater2.exe is not there anymore, then I'm sorry, but only an antivirus could do that: it might have removed it by mistake, and it keeps doing it because, if you start the Live Udpate, if Couatl_updater2.exe is missing, it should be downloaded again so, basically, unless the antivirus keeps removing it, or it's preventing the download, it's not possible for that file to be missing.