MySQl Table Crashing for no reason

[cancer10]

HI

I have a table


CREATE TABLE `poll_results` (
`id` int(5) unsigned NOT NULL auto_increment,
`poll_id` int(5) default NULL,
`poll_choice_id` int(5) default NULL,
`hits` int(5) default '0',
`status_id` tinyint(2) default '1',
PRIMARY KEY (`id`),
KEY `FK_poll_results` (`poll_id`),
KEY `FK_poll_results_choice` (`poll_choice_id`),
KEY `FK_poll_results_status` (`status_id`)
) ENGINE=MyISAM AUTO_INCREMENT=4 DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci CHECKSUM=1 DELAY_KEY_WRITE=1 ROW_FORMAT=DYNAMIC



I am running this command to insert 3 records in my new table

INSERT INTO `poll_results` (`hits`, `status_id`, `poll_id`, `poll_choice_id`) VALUES (0, 1, 1, 3);
INSERT INTO `poll_results` (`hits`, `status_id`, `poll_id`, `poll_choice_id`) VALUES (0, 1, 1, 2);
INSERT INTO `poll_results` (`hits`, `status_id`, `poll_id`, `poll_choice_id`) VALUES (0, 1, 1, 1);


All goes well until I fire this command, my table "poll_results" crashes...


UPDATE `poll_results` AS `PollResult` SET `PollResult`.`hits` = 1;

I get this error

Table 'poll_results' is marked as crashed and should be repaired



Why on earth the mysql table crash only to update 3 records?

MySql Version is 5.0.45-community-nt


Pls someone suggest.


Many thanks