I am running into this same issue, trying to restore to a month old encrypted .db file. every time i try to import, it says file not found and lists pocket.db.txt. If I change the filename, it says file not found pocket.db. if I copy the file and have one of both names in the directory, it goes back to file not found with name "pocket.db.txt"
I do have a .csv that I happened to make at that time, but when i import that in, it loses my notes, and is not silo'd per the default structure of the app.. Is there a fix to import my pocket.db file?