I rebooted the server a few times already with no change in status. I also reviewed the Wiki and then looked into the zmdailyreport script and found a "debug" option, so I ran it. 
Here is what I found:
Code:
zimbra@giskard:~$ /opt/zimbra/libexec/zmdailyreport -d
DBD::mysql::st execute failed: Table './zimbra_logger/mta' is marked as crashed and last (automatic?) repair failed at /opt/zimbra/libexec/zmdailyreport line 515.
'select distinct(quote(msgid)) from mta where arrive_time >= '2008-02-06 00:00:00' and arrive_time <= '2008-02-07 00:00:00''
/opt/zimbra/libexec/zmdailyreport sql execute failed: DBD::mysql::st fetchall_arrayref failed: fetch() without execute() at /opt/zimbra/libexec/zmdailyreport line 520.
DBD::mysql::st execute failed: Table './zimbra_logger/mta' is marked as crashed and last (automatic?) repair failed at /opt/zimbra/libexec/zmdailyreport line 515.
'select s2, count(s2) as C from (select distinct(msgid), sender as s2 from mta where sender is not null and arrive_time >= '2008-02-06 00:00:00' and arrive_time <= '2008-02-07 00:00:00') as foo group by s2 order by C desc'
/opt/zimbra/libexec/zmdailyreport sql execute failed: DBD::mysql::st fetchall_arrayref failed: fetch() without execute() at /opt/zimbra/libexec/zmdailyreport line 520.
DBD::mysql::st execute failed: Table './zimbra_logger/mta' is marked as crashed and last (automatic?) repair failed at /opt/zimbra/libexec/zmdailyreport line 515.
'select recipient, count(distinct(msgid)) as C from mta where recipient is not null and arrive_time >= '2008-02-06 00:00:00' and arrive_time <= '2008-02-07 00:00:00' group by recipient order by C desc'
/opt/zimbra/libexec/zmdailyreport sql execute failed: DBD::mysql::st fetchall_arrayref failed: fetch() without execute() at /opt/zimbra/libexec/zmdailyreport line 520.
DBD::mysql::st execute failed: Table './zimbra_logger/mta' is marked as crashed and last (automatic?) repair failed at /opt/zimbra/libexec/zmdailyreport line 515.
'select distinct(msgid), arrive_time, status, statusmsg from mta where status != 'sent' and arrive_time >= '2008-02-06 00:00:00' and arrive_time <= '2008-02-07 00:00:00' order by msgid'
/opt/zimbra/libexec/zmdailyreport sql execute failed: DBD::mysql::st fetchall_arrayref failed: fetch() without execute() at /opt/zimbra/libexec/zmdailyreport line 520.
Generating report
From 2008-02-06 00:00:00 to 2008-02-07 00:00:00
No messages found