on rwy at PHNL when i get box on screen telling me Couatl engine update available ... i click to go ahead then am told there has been a problem with the process ... now if i try to go phnl i get the crash ...
Your problem doesn't have anything to do with the scenery, or the Couatl update. The module that crashed is G3D.DLL, which usually indicates a graphic problem, possibly a corrupted/illegal scenery, but the Couatl update didn't had anything to do with PHNL, and such update couldn't caused a crash inside Prepar3D.exe, because Couatl.exe, being an external exe, can't cause a crash into another .exe.
Just to be sure you don't have a corrupted file in the scenery, try to reinstall PHNL again, of course using the latest P3D-aware installer.