Comment 16 for bug 554514

If anything you need to purge .local/share/akonadi and .config/akonadi, akonadi is KDE independent.

Anyhow, as for additional information for debugging...
1. kdebugdialog -> turn on everything
2. logout -> login
3. start akonadi by whatever means make sense (make sure the error occured)
4. logout
5. go to a terminal (tty, e.g. by pressing ctrl+alt+f1, you can go back with same for f7 OR f8) and secure the file ~/.xsession-errors
6. login
7. start akonadi (should spit out the error)
8. start akonadi again (should spit out the error or work)
9. start akonadi again (should work)
10. also secure current ~/.xsession-errors (can be from within the session)

Upload all .xsession-errors files AND the akonadi self-test reports (if possible). That should hopefully give an idea why your control process commits suicide and your error logs are dirty.

It is however, entirely possible that you just hit the startup timeout... another Kubuntu dev who is experiencing this issue is currently trying if raising the timeout helps.