Can we rule out the basics first.
Deactivate KBUR scenery in library.
Remove KBUR_ADEP4_MDM_ALT.bgl from P3D root...scenery/world/scenery (drag it to the desktop is quickest)
Fire up P3D and is default KBUR working as expected?
If yes, while at KBUR you can go to scenery library in the options menu and reactivate KBUR. The KBUR_ADEP4_MDM_ALT.bgl file will not be present in scenery/world/scenery. You should have a working airport, but surrounding autogen buildings will be up in the air. At least this is what I get on a default P3D setup.
If that works, try shutting down P3D, put KBUR_ADEP4_MDM_ALT.bgl back into scenery/world/scenery and go back to KBUR. If troubles still exist, maybe some screenshots will help me understand.