Installed, tried the 777 at Portland again with the same results. Nothing and Couatl disappearing from my addons modules area. Checked Couatl log and the info say it's v2.0 - build 2356.
I never said this would surely fix your problem. But one should always use the most current version, in order to start Troubleshooting in the correct way (it gets really confusing supporting someone without the latest set of files)
Your problem might be related to the airplane configuration, I see you used a custom config for the PMDG 737, which is not needed because that airplane is already fully supported by GSX so, if you made some kind of error editing it, it might cause unexpected problems, in case of the 777, if you made/downloaded a config before it support for it was added in GSX, your existing configuration might be using wrong data.
In both case, you should use the Reset option in the GSX Airplane configuration editor, to return to the configuration that comes with GSX. Try that and report back.