I don't know if you've tried this before, but in the ORBX folder, go into wherever the scenery is installed, go to the Southern California terrain folder, you'll see three folders, Effects, ORBX, and Scenery. Go into the ORBX folder there. Then go into the FTX_NA folder. You'll see four folders, Scenery, CVX, Mesh, and Custom. Go into the scenery folder, and you'll see another scenery folder. Go into that scenery folder. You'll want to move any file referencing KLAS, which could be ADE_FTX_SCA_KLAS.bgl, ADE_FTX_SCA_KLAS_CVX.bgl, and FTX_SCA_objects_KLAS_PLC.bgl, or some variant thereof. There should be three of those. I wouldn't recommend deleting them, but rather move them out of that scenery folder and into the previous folder that you were just in.