I can't complete the story when this one is in the way
I am sorry but the image you sent contains spoilers, even though it was a bug due to the naming of the files. However, I did understand the bug and will check it out, but can you scroll down and send it here again so we can see the rest of the traceback? Please mark it as spoiler as well. If we cannot find it from our end, we cannot fix it, so the full traceback is usually useful.
Ah upon reviewing the code, you reloaded an old save file (At least from day 8 since the variable for this one is missing). Old save files might be buggy when reloading the game due to updated codings and such. Because of this, some variables might have been deleted when updating or continuing.
I suggest start over, utilizing the skip button, and continue from there. If the error persists, let me know.
I want to again emphasize to everyone reading this to start your save file over first since Renpy is not update friendly when it comes to save files, be we do try what we can to minimize it.