Those jetways are not made by GSX, so you must be sure they are not excluded. Try to do the following:
- Remove your customization ( the KIAH .INI file in %APPDATA%\Virtuali\GSX ) , and use the one that comes with KIAH
- Remove any Exclude files for KIAH you might have in this folders:
Addon Manager\Fsdreamteam\Exclude ( XML file here )
Addon Manager\Fsdreamteam\Exclude\Scenery ( BGL file here )