I did reinstall KFLL...updated KFLL....
Have you even read the post I've linked with the solution ? It didn't say anything about "reinstalling" and "updating", jt just said to remove your custom GSX profile.
.as I taxi on to the runway..either one...the aircrafts falls and dissappears...
That's precisely because you reinstalled ( more precisely, because you updated ). As explained in the first post I linked for you, the one explaining how to download the FSX version of the AFCAD, the AFCAD which is online now
works only for P3D, if you use FSX you MUST use the old AFCAD, the one in that post. If you update with the online updater, it will revert to the P3D version, that's why the elevation now doesn't work.
Now, if you see double jetways with the FSX AFCAD, it's because the FSX AFCAD it's an old version, which contains the original custom jetways for KFLL ( not SODE ), while the P3D version doesn't have any jetways, because they come with GSX.
This means, with FSX, you must remove the GSX profile BOTH in your %APPDATA%\folder, but ALSO in the Addon Manager\Fsdreamteam\KFLL\Scenery folder because, again, just like the updated online AFCAD is for P3D, the accompanying GSX custom profile is made for it so, you can't use it in FSX, otherwise you'll see double jetways.
So, use the FSX AFCAD ( the one linked before ) and remove all GSX profiles, so the scenery will have just one set of jetways, the one it originally came with.