Error including in database: Duplicate entry '-1' for key 'PRIMARY'

Question

Friends have this table, when I save a user the following error occurs

Error including in database: Duplicate entry 'first name.last name -1' for key 'PRIMARY'

This is the code. detail in development works, not in production.

CREATE TABLE `usuarios` (
  `login` varchar(255) NOT NULL,
  `passe` varchar(255) NOT NULL,
  `nome` varchar(64) DEFAULT NULL,
  `email` varchar(255) DEFAULT NULL,
  `active` varchar(1) DEFAULT NULL,
  `activation_code` varchar(32) DEFAULT NULL,
  `admin_pv` varchar(1) DEFAULT NULL,
  `foto` longblob,
  `img_user` varchar(256) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

ALTER TABLE `usuarios`
  ADD PRIMARY KEY (`login`);