Hi,
some day s back I bought GSX and Las Vegas from you. So far very nice but I had some problems with Couatl refusing to work and thus KLAS being completely useless. For example I did yesterday do a flight with the NGX from Phoenix to Las Vegas and parked at the gate. Everything went well and the scenery behaved very well. I saved that flight with everythig working and as I returned to it, it seemed that couatl had stopped woking. I didn´t do anything between these two flights, even FSX wasn´t shut down in the meantime. I restarted FSX several times but couatl refused to work either. Luckily I was able to fix that with installing the stand alone addon manager. Now it´s working again. But such strange behaviour wasn´t the first time it occured. Just after activation the same occured but back the reloading FSX made it.
That´s just for you to know it, maybe you can find out why couatl does sometimes stop working or refuses to load.