Did you check the database to make sure that table already exists? (postfix_vacation_notification)
If it does, than no worries, the installer may be trying to add it a second time (Was a bug fix from a while back.)
DB: sentora > sentora_postfix > vacation_notification
If it does, than no worries, the installer may be trying to add it a second time (Was a bug fix from a while back.)
DB: sentora > sentora_postfix > vacation_notification