I got to tell you that downloading and installing the Addon Manager(Lastest) did not worked here.... but, doing it and reinstalling sceneries did work....
That's not what I'e said. I said there was NO need to reinstall the Stand-Alone Addon Manager too, as you said:
If upgrading to V3.4 first download install addon manager and then install your FSDT products.
That doesn't mean there wasn't any need to reinstall the sceneries.
In fact, you HAD to reinstall the sceneries, because you had a problem of a corrupted scenery.cfg file, and neither the Addon Manager or the scenery installers could fix that problem, it was you that fixed it which allowed to reinstall the sceneries correctly, but once your scenery.cfg corruption was fixed, you HAD to reinstall the sceneries.
It was the "download install addon manager" part which was redundant, and it's what I've said:
since you decided to reinstall the sceneries anyway, it's redundant.
I'll try to clarify it again:
NORMALLY, if everything's right, it's should be ENOUGH to install just the Stand-Alone Addon Manager, when updating to support a new P3D version, assuming you are only upgrading P3D, not reinstalling it from scratch.
But your situation wasn't "normal". You had a corrupted scenery.cfg, which prevented any scenery installer to complete correctly, and even the P3D own user interface to add new sceneries manually.
THAT'S why, in THIS "abormal" case, you HAD to reinstall the sceneries, and there wasn't any need to install the Stand-Alone Addon Manager as well, because all the sceneries installers comes with it.
That step was redundant if, for any reason (the reason, in this case, was the corrupted scenery.cfg file), you must reinstall the sceneries.