I had to re create my events table then drop the old from the DB to get round an issue with mysql crashing.
To do this i did the following
#mysql -p
use zabbix;
SET FOREIGN_KEY_CHECKS=0;
CREATE TABLE events_new LIKE events
INSERT INTO events_new SELECT * FROM events
ALTER TABLE events RENAME events_old
ALTER TABLE events_new RENAME events
DROP TABLE events_old
SET FOREIGN_KEY_CHECKS=1;
quit
Once you have done this run the following to check all tables are ok.
#mysqlcheck -u root -p –check –all-databases