This is not going to be much help but it sounds like you have a texture problem. Since it only seems to happen when trying to display daytime textures. You might want to try replacing the default texture by copying form one of the disk.
Unless you have added textures if you have try removing them first. Just move them out of the folder.
I do not think that this would be a scenery problem since the scenery is the same day or night it is the textrue that changes.
Sorry but I do not know which scenery FS uses for day and knowing M$ the file names wont help either as they are usually some meanigless number. 8)