there may be a mysql utf8 issue

$query_messages = "CREATE TABLE IF NOT EXISTS " . tn( MESSAGES ) . " (
				id INT NOT NULL AUTO_INCREMENT,
				title VARCHAR(200),
				text LONGTEXT,
				date DATETIME,
				link VARCHAR(200),
				author BIGINT(20),
				UNIQUE (id),
				PRIMARY KEY (id) )ENGINE=InnoDB DEFAULT CHARSET=utf8";

adding PRIMARY KEY (id) )ENGINE=InnoDB DEFAULT CHARSET=utf8 will be better!