sqlite unable to open database file

[q22]

python app.py generates this error after choosing a backup number:

Please choose a backup number and press enter: 9
Traceback (most recent call last):
File "app.py", line 107, in
with sqlite3.connect(backupPath+dictList[backupChoice]+'/3d/3d0d7e5fb2ce288813306e4d4636395e047a3d28') as message_connection:
sqlite3.OperationalError: unable to open database file