diff --git a/Classes/PHPExcel/Cell.php b/Classes/PHPExcel/Cell.php
index 454de210..66363355 100644
--- a/Classes/PHPExcel/Cell.php
+++ b/Classes/PHPExcel/Cell.php
@@ -140,7 +140,9 @@ class PHPExcel_Cell
 		$this->_parent = $pSheet;
 
 		// Set datatype?
-		if ($pDataType !== NULL) {
+		if ($pDataType !== null) {
+			if ($pDataType == PHPExcel_Cell_DataType::TYPE_STRING2)
+				$pDataType = PHPExcel_Cell_DataType::TYPE_STRING;
 			$this->_dataType = $pDataType;
 		} else {
 			if (!self::getValueBinder()->bindValue($this, $pValue)) {
@@ -624,8 +626,7 @@ class PHPExcel_Cell
 
 		// Extract range
 		if (strpos($pRange, ':') === false) {
-			$rangeA = $pRange;
-			$rangeB = $pRange;
+			$rangeA = $rangeB = $pRange;
 		} else {
 			list($rangeA, $rangeB) = explode(':', $pRange);
 		}
diff --git a/Classes/PHPExcel/Writer/Excel2007.php b/Classes/PHPExcel/Writer/Excel2007.php
index c87de9b0..9efdbd8f 100644
--- a/Classes/PHPExcel/Writer/Excel2007.php
+++ b/Classes/PHPExcel/Writer/Excel2007.php
@@ -54,7 +54,7 @@ class PHPExcel_Writer_Excel2007 implements PHPExcel_Writer_IWriter
 	 *
 	 * @var PHPExcel_Writer_Excel2007_WriterPart[]
 	 */
-	private $_writerParts;
+	private $_writerParts	= array();
 
 	/**
 	 * Private PHPExcel
@@ -68,7 +68,7 @@ class PHPExcel_Writer_Excel2007 implements PHPExcel_Writer_IWriter
 	 *
 	 * @var string[]
 	 */
-	private $_stringTable;
+	private $_stringTable	= array();
 
 	/**
 	 * Private unique PHPExcel_Style_Conditional HashTable
@@ -124,7 +124,7 @@ class PHPExcel_Writer_Excel2007 implements PHPExcel_Writer_IWriter
 	 *
 	 * @var string
 	 */
-	private $_diskCachingDirectory;
+	private $_diskCachingDirectory	= './';
 
     /**
      * Create a new PHPExcel_Writer_Excel2007
@@ -136,9 +136,6 @@ class PHPExcel_Writer_Excel2007 implements PHPExcel_Writer_IWriter
     	// Assign PHPExcel
 		$this->setPHPExcel($pPHPExcel);
 
-		// Set up disk caching location
-		$this->_diskCachingDirectory = './';
-
     	$writerPartsArray = array(	'stringtable'	=> 'PHPExcel_Writer_Excel2007_StringTable',
 									'contenttypes'	=> 'PHPExcel_Writer_Excel2007_ContentTypes',
 									'docprops' 		=> 'PHPExcel_Writer_Excel2007_DocProps',
@@ -154,8 +151,7 @@ class PHPExcel_Writer_Excel2007 implements PHPExcel_Writer_IWriter
     	//	Initialise writer parts
 		//		and Assign their parent IWriters
 		foreach ($writerPartsArray as $writer => $class) {
-			$this->_writerParts[$writer] = new $class();
-			$this->_writerParts[$writer]->setParentWriter($this);
+			$this->_writerParts[$writer] = new $class($this);
 		}
 
     	$hashTablesArray = array( '_stylesConditionalHashTable',	'_fillHashTable',		'_fontHashTable',
@@ -163,7 +159,6 @@ class PHPExcel_Writer_Excel2007 implements PHPExcel_Writer_IWriter
 							    );
 
 		// Set HashTable variables
-		$this->_stringTable = array();
 		foreach ($hashTablesArray as $tableName) {
 			$this->$tableName 	= new PHPExcel_HashTable();
 		}
diff --git a/Classes/PHPExcel/Writer/Excel2007/WriterPart.php b/Classes/PHPExcel/Writer/Excel2007/WriterPart.php
index 93d7fbde..58270d19 100644
--- a/Classes/PHPExcel/Writer/Excel2007/WriterPart.php
+++ b/Classes/PHPExcel/Writer/Excel2007/WriterPart.php
@@ -65,4 +65,17 @@ abstract class PHPExcel_Writer_Excel2007_WriterPart
 			throw new Exception("No parent PHPExcel_Writer_IWriter assigned.");
 		}
 	}
+
+	/**
+	 * Set parent IWriter object
+	 *
+	 * @param PHPExcel_Writer_IWriter	$pWriter
+	 * @throws Exception
+	 */
+	public function __construct(PHPExcel_Writer_IWriter $pWriter = null) {
+		if (!is_null($pWriter)) {
+			$this->_parentWriter = $pWriter;
+		}
+	}
+
 }