What does this message mean ?

mboxgroup8.imap_folder
note : The storage engine for the table doesn't support repair
mboxgroup8.mail_item
note : The storage engine for the table doesn't support repair
mboxgroup8.pop3_message
note : The storage engine for the table doesn't support repair
mboxgroup9.appointment
.
.
.
.
zimbra.table_maintenance
note : The storage engine for the table doesn't support repair
zimbra.volume
note : The storage engine for the table doesn't support repair

I use Utunbu 10.04LTS 64bit.

Best regards
René