diff -r 5b37998e522e -r 162c1de6545a web/lib/Zend/Exception.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/Zend/Exception.php	Fri Mar 11 15:05:35 2011 +0100
@@ -0,0 +1,96 @@
+<?php
+/**
+ * Zend Framework
+ *
+ * LICENSE
+ *
+ * This source file is subject to the new BSD license that is bundled
+ * with this package in the file LICENSE.txt.
+ * It is also available through the world-wide-web at this URL:
+ * http://framework.zend.com/license/new-bsd
+ * If you did not receive a copy of the license and are unable to
+ * obtain it through the world-wide-web, please send an email
+ * to license@zend.com so we can send you a copy immediately.
+ *
+ * @category   Zend
+ * @package    Zend
+ * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license    http://framework.zend.com/license/new-bsd     New BSD License
+ * @version    $Id: Exception.php 20978 2010-02-08 15:35:25Z matthew $
+ */
+
+/**
+* @category   Zend
+* @package    Zend
+* @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
+* @license    http://framework.zend.com/license/new-bsd     New BSD License
+*/
+class Zend_Exception extends Exception
+{
+    /**
+     * @var null|Exception
+     */
+    private $_previous = null;
+
+    /**
+     * Construct the exception
+     *
+     * @param  string $msg
+     * @param  int $code
+     * @param  Exception $previous
+     * @return void
+     */
+    public function __construct($msg = '', $code = 0, Exception $previous = null)
+    {
+        if (version_compare(PHP_VERSION, '5.3.0', '<')) {
+            parent::__construct($msg, (int) $code);
+            $this->_previous = $previous;
+        } else {
+            parent::__construct($msg, (int) $code, $previous);
+        }
+    }
+
+    /**
+     * Overloading
+     *
+     * For PHP < 5.3.0, provides access to the getPrevious() method.
+     * 
+     * @param  string $method 
+     * @param  array $args 
+     * @return mixed
+     */
+    public function __call($method, array $args)
+    {
+        if ('getprevious' == strtolower($method)) {
+            return $this->_getPrevious();
+        }
+        return null;
+    }
+
+    /**
+     * String representation of the exception
+     *
+     * @return string
+     */
+    public function __toString()
+    {
+        if (version_compare(PHP_VERSION, '5.3.0', '<')) {
+            if (null !== ($e = $this->getPrevious())) {
+                return $e->__toString() 
+                       . "\n\nNext " 
+                       . parent::__toString();
+            }
+        }
+        return parent::__toString();
+    }
+
+    /**
+     * Returns previous Exception
+     *
+     * @return Exception|null
+     */
+    protected function _getPrevious()
+    {
+        return $this->_previous;
+    }
+}