Interesting. Question: Which update did you play last before attempting to play the current one?
To explain my train of thought here: Seeing as you're (so far) the only person to show me this error leads me to believe that it's not an issue with the update itself. Then, the only time I've seen that error being persistent before, was when I switched from RenPy 7.4.8 to 7.5.3 back in like v0.13.0 (or somewhere around there).
The traceback doesn't really give too much information about what's actually wrong, so all I can really offer you is to take a look at your save file and see if I can get it to work on my end or if the save file itself somehow got borked. If you want me to do that, upload the save file to Google Drive or some other file host and send me the link as a reply here and I'll get back to you at some point tomorrow.