Error importing OJS users 2.4.8.3

I imported two user lists (author and reader) from OJS version 2.4.2 to version 2.4.8.3 but when I made the import the following error appears (below), when I migrated another user list did not appear error message.

DB Error: ERROR: null value in column “first_name” violates not-null constraint

Stack Trace:

File: /var/www/html/e-publicacoes/paginas/lib/pkp/classes/user/PKPUserDAO.inc.php line 249
Function: DAO->update(“INSERT INTO users (username, password, salutation, first_nam…”, Array(23))

File: /var/www/html/e-publicacoes/paginas/plugins/importexport/users/UserXMLParser.inc.php line 238
Function: PKPUserDAO->insertUser(Object(ImportedUser))

File: /var/www/html/e-publicacoes/paginas/plugins/importexport/users/UserImportExportPlugin.inc.php line 162
Function: UserXMLParser->importUsers(False, False)

File: /var/www/html/e-publicacoes/paginas/pages/manager/ImportExportHandler.inc.php line 43
Function: UserImportExportPlugin->display(Array(0), Object(Request))

File: (unknown) line (unknown)
Function: ImportExportHandler->importexport(Array(3), Object(Request))

File: /var/www/html/e-publicacoes/paginas/lib/pkp/classes/core/PKPRouter.inc.php line 362
Function: call_user_func(Array(2), Array(3), Object(Request))

File: /var/www/html/e-publicacoes/paginas/lib/pkp/classes/core/PKPPageRouter.inc.php line 220
Function: PKPRouter->_authorizeInitializeAndCallRequest(Array(2), Object(Request), Array(3), False)

File: /var/www/html/e-publicacoes/paginas/lib/pkp/classes/core/Dispatcher.inc.php line 134
Function: PKPPageRouter->route(Object(Request))

File: /var/www/html/e-publicacoes/paginas/lib/pkp/classes/core/PKPApplication.inc.php line 178
Function: Dispatcher->dispatch(Object(Request))

File: /var/www/html/e-publicacoes/paginas/index.php line 64
Function: PKPApplication->execute()