Sorry about that, my bad! I’ve fixed this for the next version already, but if you don't want to wait for that, you can give these instructions a try.
If you don’t have an autosave you can roll back to, first make a backup copy of your save. You can upload the .save file to a Ren'Py compatible save editor like: Save Editor Online, find player_inventory, and change:
"item_id": "scrapPaper"
to:
"item_id": "paper"
Leave the quantity and any other values unchanged. Download the edited save and replace/import the original. Deleting the entire scrapPaper entry should also fix the crash, but you’ll lose that item.