What does the error page look like? Please add an image.
the new attacks are public too, i could send the screens on discord, but you may wanna come anyway for a more immediate feedback, maybe make a short vid too, showing it happens with a fresh save and your current one.
Could also be you just screwing up the saves transfer, did you copy the hidden appdata folder when you did? or just the saves in the game folder?
260 days ago(+1)
...Never, renpy always saves data in your hidden appdata folder in users too, that's how you can safely delete your old version when you download an update and still have all your saves (and gallery).
Make sure you can view hidden files too (it's a setting you can tweak while you are looking in any folder), it should be in your pc -> users -> (your username) -> appdata -> roaming -> renpy -> tvern of spear-1. you should see all your saves, the persistent one and a sync folder, with more in, anyway, try experimenting a bit: i'd try deleting the saves from the game folder (game -> saves) and see if it all works, or copy and paste those in appdata in the saves folder (copy and paste the folders in a safe spot, maybe on the desktop, so you don't risk losing anything regardless of what you do). You could even take saves out and leave none or one or two in, who knows, maybe it's a specific save fucking everything up the instant it pops up in the saves screen in the game.