from:
http://serverfault.com/questions/183725/error-not-found-or-unable-to-stat-in-apache-logs-and-difference-in-httpd-confWhen this error starts populating your logs, you will be unable to access any information from your MySQL table. The fix is easy,
simply run a REPAIR TABLE on the affected table and your issue should be solved.
mysql>REPAIR TABLE <database>.<tablename>
But simply fixing the table wasn’t enough. I wanted to know what caused the table corruption in the first place. After a bit of research it looks like there are a number of possible reasons:
MySQL process is killed unexpectedly
Hardware issues
MySQL code or MyISAM/InnoDB code is suffering from bugs
An external program and server is modifying the same table at the same time
Unexpected system shutdown
... so i really have no real idea of why we failed.