Have you uninstalled the previous version before trying to install the new one? You'll most likely have to back up your saves as well, but if that's not feasible for some reason, you can also skip chapters if your saves get lost in the process.
Gotcha. I figured that might be the case, but wanted to ask to cover my bases.
:)
Honestly, I won't be too upset if I have to replay everything up till now; this is so far one of my favorite VNs I've played and not even for the lewd shit. I'm actually really impressed at the quality of writing and the diversity of characters and personalities that all stand out without being either too over the top or similar to each other!
Very well done!