Have you already seen this error with OfflineIMAP and Sqlite3?
Creating new Local Status db for Local-Gmail:INBOX-journal ERROR: While attempting to sync account 'GMail' file is encrypted or is not a database
Oh god, one of your databases is corrupted. This corruption is usually caused by an interruption during processing an account. But don't worry, the fix is quite simple.
First go on
.offlineimap/Account-<YourAccountName>/LocalStatus-sqlite, open the file
INBOX with sqlite3 and type
pragma integrity_check; (and press Enter):
SQLite version 188.8.131.52 2012-10-04 19:37:12 Enter ".help" for instructions Enter SQL statements terminated with a ";" sqlite> pragma integrity_check;
Now you can quit with
.quit and restart offlineimap.