Bundybroham, change your colors from x16 bit to x32bit (24bits + 8 bits for alpha channel) which basically means you get twice as many colors, that is why you are getting green colors, you're currently getting ~8mil colors and you are supposed to get ~16mil. And don't worry it doesn't lag your game or PC, it just processes colors not actual textures.
Settings > Video > Resolution (width × height x 32bit colors) > ok
While you're there you could upgrade your AA (anti aliasing) to x16 as it smoothens the edges of every texture, though that actually takes quite a lot more processing power to render the textures, but it is a 10 year old game, you surely can run it smoothly