You haven’t given much information.
Did you use the in-game menu to change the color? IE: Escape – color manager or whatever it’s called – and then changed the color?
Or did you muddle around in the files?
I couldn’t duplicate this issue using the color manager. It changed fine for me, changing multiple colors with no problem.
Based on the error message provided, the game is looking for the color “white” which it doesn’t think exists. Without knowing exactly what you did, I have no idea. There’s no issues I saw on Github, and if you’re unable to undo what you did, you’ll probably have to fresh install the game.
If you’re on the same version, you should be able to move your saves to the new directory without issue.