Error when updating with foreign keys with ON UPDATE CASCADE - mysql

Question

I have this table:
CREATE TABLE `user` (
`idUser` char(13) NOT NULL,
`contrasena` varchar(50) NOT NULL DEFAULT '',
`fechaInicio` datetime DEFAULT NULL,
`emailRegistrado` varchar(100) DEFAULT NULL,
`tipoUsuario` int(11) NOT NULL,
PRIMARY KEY (`idUser`),
KEY `tipoUser` (`tipoUsuario`) USING BTREE,
CONSTRAINT `tipoUser` FOREIGN KEY (`tipoUsuario`) REFERENCES `tipo_user` (`idTipo`) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf16;
And then this table:
CREATE TABLE `alumno` (
`idAlumno` char(10) NOT NULL DEFAULT '',
`Nombre` varchar(60) NOT NULL,
`ApePaterno` varchar(30) NOT NULL,
`ApeMaterno` varchar(30) NOT NULL,
`CURP` varchar(18) DEFAULT NULL,
`Sexo` enum('H','M') NOT NULL,
`FechaNac` date NOT NULL,
`Estado_Nac` int(11) DEFAULT NULL,
`Nacionalidad` int(11) DEFAULT NULL,
PRIMARY KEY (`idAlumno`),
KEY `fk_Alumno_Estados1_idx` (`Estado_Nac`) USING BTREE,
KEY `fk_Alumno_Pais1_idx` (`Nacionalidad`) USING BTREE,
CONSTRAINT `fk_Alumno_Estados1` FOREIGN KEY (`Estado_Nac`) REFERENCES `estadomexico` (`idEstados`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `fk_Alumno_Pais1` FOREIGN KEY (`Nacionalidad`) REFERENCES `pais` (`idPais`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `fk_Al_User` FOREIGN KEY (`idAlumno`) REFERENCES `user` (`idUser`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf16;
When I try to update a value for a user, MySQL throws the following message:
Cannot delete or update a parent row: a foreign key constraint fails (mydb.empleado, CONSTRAINT fk_Empleado_USer FOREIGN KEY
(idEmpleado) REFERENCES user (idUser) ON DELETE CASCADE ON
UPDATE CASCADE)
Can anybody please help me?