title: Call to undefined method PHPExcel::sheetNameExists() When Loading a Template Excel File
body: <p>I am trying to load an excel template:</p>
  
  <pre><code>require_once BASEPATH .'libraries/PHPExcel/IOFactory.php';
  $objPHPExcel = PHPExcel_IOFactory::load($filename);
  </code></pre>
  
  <p>and it throws an Error:</p>
  
  <pre><code>Call to undefined method PHPExcel::sheetNameExists() in ...\libraries\PHPExcel\Worksheet.php on line 809
  </code></pre>
  
  <p>I checked <code>$filename</code> and the file is existing.</p>
  
  <p><strong>Spec:</strong></p>
  
  <p><strong>PHPExcel:</strong> v. 1.7.6, 2011-02-27</p>