I haven't played the game before and just downloaded it for the first time through the links at the top of the thread, so I don't think it would have anything to do with modding. I checked the appdata folder anyway to make sure and it was empty, so that almost certainly isn't problem. I deleted an re-installed it a couple of times and that yielded no results either, so idk.You're probably going from a modded to an unmodded version of the game. Mod no longer exists, so it won't work. I can't/don't provide support for mod problems, so... Try reinstalling from scratch and deleting out your save and persistent data from %APPDATA%. No one playing an unmodified version has had issues with running Ch 11.