Site went down. database repair

Can anyone tell me what this means?
It’s from my logs telling me why my Worpress.org site went down. I still am having to do daily repairs to the databse. Thank you.

PHP Warning: Cannot modify header information – headers already sent by (output started at /leadershipskills/wp-content/plugins/stats/stats.php:113) in /leadershipskills/wp-content/plugins/stats/stats.php on line 365 [04-Nov-2011 17:20:33] WordPress database error Can’t open file: ‘wp_comments.MYI’ (errno: 144) for query SELECT wp_comments.* FROM wp_comments WHERE comment_post_ID = ‘1294’ AND comment_approved = ‘1’ ORDER BY comment_date_gmt DESC LIMIT 10 made by require, wp, WP->main, WP->query_posts, WP_Query->query, WP_Query->get_posts [04-Nov-2011 17:20:33] WordPress database error Can’t open file: ‘wp_postmeta.MYI’ (errno: 144) for query SELECT post_id, meta_key, meta_value FROM wp_postmeta WHERE post_id IN (1294) made by require, wp, WP->main, WP->query_posts, WP_Query->query, WP_Query->get_posts, update_post_caches, update_postmeta_cache, update_meta_cache