Offlineimap succeeds at prompt but fails via cron job

[Joseph LP]

In the hopes to get more debugging messages, my crontab entry now looks like
this:

> 0 * * * * /usr/bin/offlineimap -1 -d imap,maildir,thread

The results of the back-trace are now at http://paste2.org/p/539446

(as individual lines exceed gmane's 80 char limit. As far as I can tell, imap
auth succeeds.)

Are there any obvious issues from the back-trace?