I installed and reinstalled KIAH in FSX many times always with antivirus and firewall not active but always with the same result.
The same software was installed in P3Dv4.1 only once without problems.
In these images the difference between FSX and P3Dv4.1
"P3Dv4.1 Runway view FSDT KIAH scenery Active"
https://ibb.co/grPxPG "FSX Runway view FSDT KIAH scenery Active"
https://ibb.co/dAa7rw "P3Dv4.1 Topdown view FSDT KIAH scenery Active"
https://ibb.co/kGN6Jb "FSX Topdown view FSDT KIAH scenery Active"
https://ibb.co/kc57rw As seen in this image the landing strips are covered by a gray spot that prevents you from seeing the runways.
Zooming in on the topdown image you can see the runway and the positioning of the plane.
"FSX Topdown zoom view FSDT KIAH scenery Active"
https://ibb.co/jc0e4G I tried to see if there were other 'bgl' files in addition to those of FSDT but the only file appeared to be the one installed.
I tried to restore the backup file of the live update, same result.
In the scenery.cfg file, I first made inactive only the area of FSDT KIAH and after all those of ORBX and the result obtained is, in both cases, the disappearance of the gray spot as it results from the two successive images.
"FSX Topdown view FSDT KIAH scenery inactive"
https://ibb.co/jWWadb "FSX Topdown view FSDT KIAH and ORBX scenery inactive"
https://ibb.co/mbACPG I modify also the scenery.cfg file using only the default areas of FSX plus FSDT KIAH.
Also this way in the Topdown image is visible the grey spot above the airport.
GSX is installed.
What can I do to solve this display problem? 
