Same problem here. I can activate the LSGG Addon via the Addon Manager, but it say : product is activated but not in the Scenery Libary. I spawn in LSGG on the RW. I have the same problem with the LSGG Airport Texture, but i can see the addoon runway and taxiway textures.
Los Angeles, KJFK, Vancouver works very good. The problem Airport is LSGG.
And a good friend maked yesterday a Addon Manager update, after that he has the same problem in lsgg.
And yes, i can see under Addons the Couatl and Addon Manager