Your answer doesen't really provide a solution? The question was (and I need it too) how do you update the addon manager?
Well, the question was "How do you update your addon manager to get rid of crash to desktop".
To that question, my answer was correct, because a quit or crash to desktop happens only if some files of the Addon Manager are not updated, which can only happen if one ran an old installer (for example, old Cloud9 ones) that didn't self-update these files from the internet, something that all our current installers do.
This means, to fix the problem mentioned in the original question, it was enough to run any of our scenery installer, and the most current Addon Manager files would have been automatically fetched from the server. Of course, excluding antivirus interference, which is also a cause for a mix-up between version (if antivirus blocks the download of the update).
This answers the original question.
If, instead, you need to update the whole Addon Manager, because you got the message at startup from Couatl, suggesting to install the Stand-Alone Addon Manager, in this case it's a different issue, that doesn't cause any crash to desktop, but it requires to update files which are not part of the self-update routine that is included in all scenery installers.
In this case, the solution is exactly what the message says: download and install the Stand-Alone Addon Manager.
There are download links for it in every "Info" page for every product, and it's also repeated in the FAQ page.