RogueNine
Warlord
BUG hasn't used a centralized "BUG Mod.ini" file for quite some time (over a year). Were you loading an old save or starting a new game? Did the installer warn you about files in the CustomAssets folder? Did you let it rename the folder?
I was loading an old save, although after I uninstalled-reinstalled BUG, rebooted and started a new Civ game, it still gave me that error. I got no warning about files in the customassets folder (the uninstaller of BUG 3.whatever took those out I believe). No prompt for a folder renaming, so not sure what that even means, but that can't be good.

What should I do?
Thanks for the reply.