I have file "/home/user/.calendar/calendardb" - and my Calendar is fine. So, copy file "/home/user/.calendar/calendardb.backup" to another place (like, "/home/user/MyDocs") just-in-case, and then copy it to "/home/user/.calendar/calendardb" - maybe, Calendar will be able to read it, then. If "/home/user/.calendar/calendardb" disappears - I don't know why it would disappear - you will be glad to have a copy of it safe somewhere else (like, in "/home/user/MyDocs"). If Calendar reads the entries - it might require "killall Calendar" in X-Term as non-root - then you will be glad that Maemo backed up your database, and it wasn't lost during unexpected reboot. Merely misplaced. Best wishes.