title: PHPExcel (Version 1.7.8), Fatal error: Call to a member function getRange() on a non-object
body: <p>I arleady posted this question on the CodePlex forum... but to no avail yet...</p>
  
  <p>I have developed code that creates an array to hold a report structure and then dumps it into excel. So far it has been working flawlessly (in Window 7 Ultimate) until I upgraded to Windows 7 Enterprise... </p>
  
  <p>I am now getting an error which is echoed onto the xlsx file and therefore renders it totally corrupt. I am wondering at this sudden change of behaviour... I copy the error here below. (I am running PHPExcel 1.7.8, version 5.3.8 of PHP and 2.2.21 of Apache): </p>
  
  <p><code>Fatal error: Call to a member function getRange() on a non-object in C:\wamp\www\istudium\Classes\PHPExcel\Writer\Excel2007\Workbook.php on line &lt;i&gt;350&lt;/i&gt;&lt;/th&gt;&lt;/tr&gt;</code></p>