diff --git a/Classes/PHPExcel/Settings.php b/Classes/PHPExcel/Settings.php
index 3b5d7629..e157e87c 100644
--- a/Classes/PHPExcel/Settings.php
+++ b/Classes/PHPExcel/Settings.php
@@ -42,6 +42,13 @@ class PHPExcel_Settings
 	const ZIPARCHIVE	= 'ZipArchive';
 
 
+	/**
+	 *	Reference to the class used for Zip file management
+	 *		e.g.
+	 *			ZipArchive
+	 *
+	 *	@var string
+	 */
 	private static $_zipClass	= self::ZIPARCHIVE;
 
 
diff --git a/Classes/PHPExcel/Shared/ZipArchive.php b/Classes/PHPExcel/Shared/ZipArchive.php
index 12d306da..724e771a 100644
--- a/Classes/PHPExcel/Shared/ZipArchive.php
+++ b/Classes/PHPExcel/Shared/ZipArchive.php
@@ -38,6 +38,11 @@ require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/PCLZip/pclzip.lib.php';
 class PHPExcel_Shared_ZipArchive
 {
 
+	/**	constants */
+	const OVERWRITE		= 'OVERWRITE';
+	const CREATE		= 'CREATE';
+
+
 	/**
 	 * Temporary storage directory
 	 *
diff --git a/Classes/PHPExcel/Writer/Excel2007.php b/Classes/PHPExcel/Writer/Excel2007.php
index b44aa7df..477d2db0 100644
--- a/Classes/PHPExcel/Writer/Excel2007.php
+++ b/Classes/PHPExcel/Writer/Excel2007.php
@@ -224,12 +224,18 @@ class PHPExcel_Writer_Excel2007 implements PHPExcel_Writer_IWriter
 			$zipClass = PHPExcel_Settings::getZipClass();
 			$objZip = new $zipClass();
 
+			//	Retrieve OVERWRITE and CREATE constants from the instantiated zip class
+			//	This method of accessing constant values from a dynamic class should work with all appropriate versions of PHP
+			$ro = new ReflectionObject($objZip);
+			$zipOverWrite = $ro->getConstant('OVERWRITE');
+			$zipCreate = $ro->getConstant('CREATE');
+
 			if (file_exists($pFilename)) {
 				unlink($pFilename);
 			}
 			// Try opening the ZIP file
-			if ($objZip->open($pFilename, ZIPARCHIVE::OVERWRITE) !== true) {
-				if ($objZip->open($pFilename, ZIPARCHIVE::CREATE) !== true) {
+			if ($objZip->open($pFilename, $zipOverWrite) !== true) {
+				if ($objZip->open($pFilename, $zipCreate) !== true) {
 					throw new Exception("Could not open " . $pFilename . " for writing.");
 				}
 			}
diff --git a/changelog.txt b/changelog.txt
index b880fce8..d5b5e694 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -25,6 +25,7 @@
 
 Fixed in SVN:
 - Bugfix:   (MBaker) Work item 15459 - Invalid cell coordinate in Autofilter for Excel2007 Writer
+- Bugfix:   (MBaker) Work item 15518 - PCLZip library issue
 - General:	(MBaker) Work item 15405 - Two easy to fix Issues concerning PHPExcel_Token_Stack (l10n/UC)
 - General:	(MBaker) Work item 15461 - Locale file paths not fit for windows