diff --git a/Classes/PHPExcel/Shared/OLE/PPS/Root.php b/Classes/PHPExcel/Shared/OLE/PPS/Root.php
index a3c4ab6d..6168443d 100644
--- a/Classes/PHPExcel/Shared/OLE/PPS/Root.php
+++ b/Classes/PHPExcel/Shared/OLE/PPS/Root.php
@@ -29,12 +29,21 @@
 */
 class PHPExcel_Shared_OLE_PPS_Root extends PHPExcel_Shared_OLE_PPS
 	{
+
+	/**
+	 *	Directory for temporary files
+	 *	@var string
+	 */
+	protected $_tmp_dir
+
 	/**
 	 * @param integer $time_1st A timestamp
 	 * @param integer $time_2nd A timestamp
 	 */
 	public function __construct($time_1st, $time_2nd, $raChild)
 	{
+		$this->_tempDir = PHPExcel_Shared_File::sys_get_temp_dir();
+
 		parent::__construct(
 		   null,
 		   PHPExcel_Shared_OLE::Asc2Ucs('Root Entry'),
diff --git a/changelog.txt b/changelog.txt
index 252cb27f..66dc2dbc 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -61,6 +61,7 @@ Fixed in SVN:
 						Fix Excel2007 Writer to handle print areas that are defined as row or column ranges rather than just as cell ranges
 - Bugfix:	(MBaker) Reduced false positives from isDateTimeFormatCode() method by suppressing testing within quoted strings
 - Bugfix:	(MBaker) Work item 15312 - Caching and tmp partition exhaustion 
+- Bugfix:	(MBaker) Work item 15308 - Writing to Variable No Longer Works. $_tmp_dir Missing in PHPExcel\PHPExcel\Shared\OLE\PPS\Root.php
 - General:  (MBaker) Improved performance (speed), for building the Shared Strings table in the Excel2007 Writer.
 - General:  (MBaker) Enhanced SheetViews element structures in the Excel2007 Writer for frozen panes.