From time to time MySQL corrupts itself. This message means that your table needs repair, however, the option for repair through the PHPMyAdmin interface is not available. Under some situations however, no matter how many times you run a REPAIR on the table, the table still returns IN USE and what's worse is that the system says the table is "already up to date".
Therefore, you need to open a terminal or ssh (Putty) and run the following commands:
cd /usr/local/MySQL/var/ragnarok (where "ragnarok" is the one you're trying to fix)
myisamchk --safe-recover char (where "char" is the table you are trying to fix)
This will repair the table in safe mode or your table will be fixed in a few minutes!
