Pretty PO'd now. After starting FSX to be told that my addon manager was out of date ALL my FSD sceneries are now non-functional.
That message didn't said just that. It also said that downloading and installing the Stand-Alone Addon Manager would have fixed the problem.
I've rebooted, removed, reinstalled, reactivated, updated the ridiculous addon manager, and reinstalled again, disabled all security scanning, etc, etc, etc.
The message didn't said anything about rebooting, reinstalling and reactivating.
And besides, you surely haven't "reactivated", since reactivation can only be done if you change your hardware, just reinstalling will doesn't require reactivation and it's not even possible, since the "Register Serial" option is greyed our if your scenery is active, and the only way to make it no-active again it's either changing hardware OR manually cleaning the serial numbers from the registry.
You ONLY had to download and install the updated Addon Manager using its Stand-Alone installer, as the message said.
"...\FSX\fsdreamteam\couatl\wx\_controls.pyd is either not designed to run on Windows (ha! nice!) or it contains an error. Try installing the program again using the original installation media or contact... blah blah" Apparently the latest downloads from FSDT don't meet that requirement?
This because you, instead of doing exactly what the message said, removed and reinstalled the sceneries themselves, using old installers you had which is not what the message said. The message said to download and install the Stand-Alone Addon Manager.
SO, after re-downloading all my FSDT purchases, removing addon manager, couatl, all my sceneries, restarting the pc, rinstalling them again, nothing.
This wasn't needed at all, it could have worked but, in this case, you had to pay attention to install the most recent scenery as last but, as I've said, this wasn't needed.
The whole point of having a separate Addon Manager installed, is that you can download only *that* one, and update everything that needs to be updated, without having to redownload everything and without worrying about the order of the installation.
The Stand-Alone Addon Manager must be run AFTER all the sceneries installed. Which is the normal situation you should be if you simply install it after reading the "outdated Addon Manager" message.
All this so that my addon manager could be updated to the latest version; highly important considering once set correctly it's a forgotten entry. 
Nothing of what you did was needed. The only thing that was needed and would have fixed the problem, was to download and install the Stand-Alone Addon Manager only, as the message said.
Lesson learned; if I ever do manage to reclaim my purchased software into some functioning form the very next step will be blocking all outbound connections form this mess...
Better said, next time you see a message, do exactly what the message says, to the letter. If you encounter any problems, ask for help first.
