Well you could try replacing the following in the Misc folder:
Nori00.tga
Nori01.tga
CloudsTransition.tga
Or you could try these in the Env folder, just make sure you select 8k or 16k files:
SkyColors_Arct.dat
SkyColors_Atl.dat
SkyColors_Med.dat
Maybe one of these is corrupt?
