Hi, I have the same issue as Jimcho has.
Currently, I have the Las Vegas scenery installed on my new Win 7, 64-bit OS and I see this problem. When I'm on runway 25R looking west from the PMDG 747-400 (the cockpit is high off the ground) you can see this semi-transparent image below the surface of the runway very easily. In addition, down runway 25R, there is a structure with a tower next to a red and white checkerboard building between RW 25R and RW 25L......note that there are two of these structures when there should only be one.
However, if I return to my older PC set up running Win XP, 32 bit, this problem doesn't appear at all. The runway looks as you would expect it to be, and the duplicate red and white checkerboard is not there (only one building appears). I'm keeeping this older system alive until I work thru all the issues of a new setup before I convert it to another use.
Could the issue be due to the Win 7 or 64-bit difference?
Bill