dbDelta problems

        dbDelta("        CREATE TABLE {$wpdb->prefix}pubmedarticles (        pubmed_id mediumint NOT NULL,        cat_id varchar(20) NOT NULL,        title tinytext NOT NULL,        volume tinyint UNSIGNED NOT NULL,         issue tinyint UNSIGNED NOT NULL,         pubdate date NOT NULL,        journal_abbrev varchar(20) NOT NULL,        pagination varchar(10) NOT NULL,        abstract longtext NOT NULL,        INDEX (pubmed_id)        );         ");