Have you tried posting on the Tech Support sub forum for the game (CMBN?) on BattleFront's Forum boards? Lots of knowledgeable / helpful guys on there.
I'm only guessing, but it may e.g. be a hardware/driver issue with your specific machine and graphics card?
Only other thought that occurs to me is mods: do you have any installed? If they need updating to a newer version for compatibility with a later version of the game itself, IIRC that may cause issues like this. (Also, if you do have mods installed, it seems to be recommended practice to move the mods ("z") folder somewhere else whilst you patch/upgrade/move the game files, and then put the mods folder back again afterwards.)
Don't know if any of that applies / helps!
