I don't know about the errors, but you can go to C:\Users\(Computer Username)\AppData\Roaming\RenPy to delete saves. Also check your keyboard, cuz mine has multiple delete buttons.
On a Mac they’re located under your home folder in Library/RenPy/ExtracurricularActivities. (Library is usually hidden, but if you open a finder window on your user home folder and hit command-shift-period then it’ll show hidden folders.)
