The error looks like it is part of the new functionality to set quotas for users. Somehow, your database already has the required table structure. Did you in the past already try that functionality? (it has been in beta very long)
You might get away with this by either:
- Editing /home/user-data/mailinabox.version. It should contain 14, set it to 15
- Edit your sqlite database directly, removing the quota column.
No guarantees, and of course make sure you have backups.