Duplicate entry 'Exotical' for key 'naam'

CREATE TABLE IF NOT EXISTS `ht_users` (
  `id` int(11) NOT NULL,
  `last_seen` varchar(55) NOT NULL,
  `naam` varchar(50) NOT NULL,
  `pass` varchar(100) NOT NULL,
  `pin` varchar(100) DEFAULT NULL,
  `email` varchar(100) NOT NULL,
  `email_activation` varchar(100) NOT NULL,
  `last_ip` varchar(15) NOT NULL,
  `reg_ip` varchar(15) NOT NULL,
  `reg_date` varchar(10) NOT NULL,
  `last_login` varchar(8) NOT NULL DEFAULT '00000000',
  `rank` varchar(4) NOT NULL,
  `rank2` varchar(4) DEFAULT NULL,
  `kladblok` text,
  `listenerminutes` int(11) NOT NULL DEFAULT '0',
  `shouts_liked` int(11) NOT NULL DEFAULT '0',
  `mail_solli` enum('0','1') NOT NULL DEFAULT '1',
  `mail_event` enum('0','1') NOT NULL DEFAULT '1',
  `online` varchar(12) NOT NULL DEFAULT '000000000000',
  `skype` varchar(20) NOT NULL,
  `permban` enum('0','1') NOT NULL DEFAULT '0',
  `goldrecords` int(11) NOT NULL DEFAULT '0',
  `signature` text NOT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `naam` (`naam`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1;