$c = 'test1.xls';
$objPHPexcel = PHPExcel_IOFactory::load('orig.xlsx');
$objWorksheet = $objPHPexcel->getActiveSheet();
$objWorksheet->getCell('R17C7')->setValue('Тестовое Имя');
$objWriter = PHPExcel_IOFactory::createWriter($objPHPexcel, 'Exce15');
$objWriter->save($c);?>Excel5 на Excel2007 в строке PHPExcel_IOFactory::createWriter($objPHPexcel, 'Exce15');PHPExcel_IOFactory::createWriter($objPHPexcel, 'Excel2007');Exce15, наверно имелось ввиду Excel5