You may get this warning when you take full MySQL server backup on above MySQL 5.2 GA version.This warnings cab be ignored since it is related to MySQL new feature “Event Scheduler”.
Solution : You may simply add parameter “–ignore-table=mysql.event” along with MySQL Dump command.
Or you may add the following lines in MySQL config (/etc/my.cnf). file but it requires a service restart. So I do not recommend.
So simple ..