Hmm, that sounds like renpy is trying to define something as both true and false at the same time. This should completely break the game, and since others are playing fine, I think we can assume at the moment this is a local issue.
I'm not a expert on the inner workings of renpy, but at the moment, I am thinking this is an issue with the download or a corruption in the persistent data (or both).
Please can you try the following steps.
1. Delete the game folder and all past versions of the game folder, as we need a fresh install.
2. Then delete your persistent data. This is usually found C:\Users\<you>\AppData\Roaming\RenPy\ - don't delete the whole renpy folder, just the folder for the Thorns of War should do it. It should be a called something like 'The Thorns of War - 1234567890'.
Doing the above should remove any persistent data and save files that might have been corrupted between versions.
3. Now we are sure renpy isn't going to be reading any old data, you can re-download versions 2.8 and, with any luck, find the problem has resolved.
Please let me know how you get on - I really hope this works for you