Para cada tabela Wordpress, adicione sua chave desta forma (veja a penúltima linha):
CREATE TABLE IF NOT EXISTS `wp_commentmeta` (
`meta_id` bigint(20) unsigned NOT NULL auto_increment,
`comment_id` bigint(20) unsigned NOT NULL default '0',
`meta_key` varchar(255) default NULL,
`meta_value` longtext,
key (meta_id) -- add this line (remember to add the comma in the previous line)
) ENGINE=MyISAM AUTO_INCREMENT=236 DEFAULT CHARSET=utf8;
Tabelas Wordpress:
wp_commentmeta
wp_comments
wp_links
wp_options
wp_postmeta
wp_posts
wp_terms
wp_term_relationships
wp_term_taxonomy
wp_usermeta
wp_users
