stò cercando di creare un excel per ricavare i dati da un db ma sono bloccato non riesco a mettere lòe intestazioni alle colonne della tabella:

<?php
error_reporting(E_ALL);
date_default_timezone_set('Europe/Rome');
require_once 'Classes/PHPExcel.php';
$objPHPExcel = new PHPExcel();
$objPHPExcel->getProperties()->setCreator("Luigi")

->setLastModifiedBy("Luigi")
->setTitle("Office 2007 XLSX Test Document")
->setSubject("Office 2007 XLSX Test Document")
->setDescription("Test document for Office 2007 XLSX, generated using PHP classes.")
->setKeywords("office 2007 openxml php")
->setCategory("Test result file");

$objPHPExcel->setActiveSheetIndex(0);

$objPHPExcel->getDefaultStyle()->getFont()->setName('Arial');
$objPHPExcel->getDefaultStyle()->getFont()->setSize(10);

$objPHPExcel->getActiveSheet()->getColumnDimension('A')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('B')->setWidth(18); //Fixed this column to enter the print margin
$objPHPExcel->getActiveSheet()->getColumnDimension('C')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('D')->setAutoSize(true);
$objPHPExcel->getActiveSheet()->getColumnDimension('E')->setWidth(15); //Fixed this column to enter the print margin
$objPHPExcel->getActiveSheet()->getColumnDimension('F')->setWidth(9); //Fixed this column to enter the print margin
$objPHPExcel->getActiveSheet()->getColumnDimension('G')->setAutoSize(true);


header('Content-Type: application/vnd.ms-excel');
header('Content-Disposition: attachment;filename="Prova.xls"');
header('Cache-Control: max-age=0');

$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel5');
$objWriter->save('php://output');
exit;

fino a questo punto mi apre l'excel na se inserisco questo prima dell'header, siblocca tutto

$objPHPExcel->setActiveSheetIndex(0)
->setCellValue('A' . $iIndexDetailCalls, 'Numero')
->setCellValue('B' . $iIndexDetailCalls, 'Data')
->setCellValue('C' . $iIndexDetailCalls, 'Durata')
->setCellValue('D' . $iIndexDetailCalls, 'Tipo')
->setCellValue('E' . $iIndexDetailCalls, 'Prefisso')
->setCellValue('F' . $iIndexDetailCalls, 'Prezzo')
->setCellValue('G' . $iIndexDetailCalls, 'Destino');

$styleThinBlackBorderOutline = array(
'borders' => array(
'outline' => array(
'style' => PHPExcel_Style_Border::BORDER_THICK,
'color' => array('argb' => 'FF6B7C6B'),
),
),
);

dove sbaglio? grazie