diff --git a/phpBB/common.php b/phpBB/common.php
index 9b6913e95f..6cc7abf118 100644
--- a/phpBB/common.php
+++ b/phpBB/common.php
@@ -188,6 +188,7 @@ if (!empty($load_extensions) && function_exists('dl'))
 }
 
 // Include files
+require($phpbb_root_path . 'includes/class_loader.' . $phpEx);
 require($phpbb_root_path . 'includes/acm/acm_' . $acm_type . '.' . $phpEx);
 require($phpbb_root_path . 'includes/cache.' . $phpEx);
 require($phpbb_root_path . 'includes/template.' . $phpEx);
@@ -211,6 +212,9 @@ $template	= new template();
 $cache		= new cache();
 $db			= new $sql_db();
 
+$class_loader = new phpbb_class_loader($phpbb_root_path, '.' . $phpEx, $cache);
+$class_loader->register();
+
 // Connect to DB
 $db->sql_connect($dbhost, $dbuser, $dbpasswd, $dbname, $dbport, false, defined('PHPBB_DB_NEW_LINK') ? PHPBB_DB_NEW_LINK : false);
 
diff --git a/phpBB/includes/auth/auth_db.php b/phpBB/includes/auth/auth_db.php
index 73c4f92976..b672e212bf 100644
--- a/phpBB/includes/auth/auth_db.php
+++ b/phpBB/includes/auth/auth_db.php
@@ -69,7 +69,7 @@ function login_db(&$username, &$password)
 	if ($show_captcha)
 	{
 		// Visual Confirmation handling
-		if (!class_exists('phpbb_captcha_factory'))
+		if (!class_exists('phpbb_captcha_factory', false))
 		{
 			global $phpbb_root_path, $phpEx;
 			include ($phpbb_root_path . 'includes/captcha/captcha_factory.' . $phpEx);
@@ -90,7 +90,7 @@ function login_db(&$username, &$password)
 		{
 			$captcha->reset();
 		}
-		
+
 	}
 
 	// If the password convert flag is set we need to convert it
diff --git a/phpBB/includes/captcha/plugins/phpbb_captcha_gd_plugin.php b/phpBB/includes/captcha/plugins/phpbb_captcha_gd_plugin.php
index 6e899adc16..a326074c14 100644
--- a/phpBB/includes/captcha/plugins/phpbb_captcha_gd_plugin.php
+++ b/phpBB/includes/captcha/plugins/phpbb_captcha_gd_plugin.php
@@ -19,7 +19,7 @@ if (!defined('IN_PHPBB'))
 /**
 * Placeholder for autoload
 */
-if (!class_exists('phpbb_default_captcha'))
+if (!class_exists('phpbb_default_captcha', false))
 {
 	include($phpbb_root_path . 'includes/captcha/plugins/captcha_abstract.' . $phpEx);
 }
diff --git a/phpBB/includes/captcha/plugins/phpbb_captcha_gd_wave_plugin.php b/phpBB/includes/captcha/plugins/phpbb_captcha_gd_wave_plugin.php
index 2f55d15efd..8ac0262302 100644
--- a/phpBB/includes/captcha/plugins/phpbb_captcha_gd_wave_plugin.php
+++ b/phpBB/includes/captcha/plugins/phpbb_captcha_gd_wave_plugin.php
@@ -19,7 +19,7 @@ if (!defined('IN_PHPBB'))
 /**
 * Placeholder for autoload
 */
-if (!class_exists('phpbb_default_captcha'))
+if (!class_exists('phpbb_default_captcha', false))
 {
 	include($phpbb_root_path . 'includes/captcha/plugins/captcha_abstract.' . $phpEx);
 }
diff --git a/phpBB/includes/captcha/plugins/phpbb_captcha_nogd_plugin.php b/phpBB/includes/captcha/plugins/phpbb_captcha_nogd_plugin.php
index ac30ed4297..834d2a7f12 100644
--- a/phpBB/includes/captcha/plugins/phpbb_captcha_nogd_plugin.php
+++ b/phpBB/includes/captcha/plugins/phpbb_captcha_nogd_plugin.php
@@ -19,7 +19,7 @@ if (!defined('IN_PHPBB'))
 /**
 * Placeholder for autoload
 */
-if (!class_exists('phpbb_default_captcha'))
+if (!class_exists('phpbb_default_captcha', false))
 {
 	include($phpbb_root_path . 'includes/captcha/plugins/captcha_abstract.' . $phpEx);
 }
diff --git a/phpBB/includes/captcha/plugins/phpbb_captcha_qa_plugin.php b/phpBB/includes/captcha/plugins/phpbb_captcha_qa_plugin.php
index 49a64b9339..c0cdc83fa1 100644
--- a/phpBB/includes/captcha/plugins/phpbb_captcha_qa_plugin.php
+++ b/phpBB/includes/captcha/plugins/phpbb_captcha_qa_plugin.php
@@ -87,7 +87,7 @@ class phpbb_captcha_qa
 			}
 			$db->sql_freeresult($result);
 		}
-	
+
 		// okay, if there is a confirm_id, we try to load that confirm's state. If not, we try to find one
 		if (!$this->load_answer() && (!$this->load_confirm_id() || !$this->load_answer()))
 		{
@@ -113,7 +113,7 @@ class phpbb_captcha_qa
 	{
 		global $db, $phpbb_root_path, $phpEx;
 
-		if (!class_exists('phpbb_db_tools'))
+		if (!class_exists('phpbb_db_tools', false))
 		{
 			include("$phpbb_root_path/includes/db/db_tools.$phpEx");
 		}
@@ -365,12 +365,12 @@ class phpbb_captcha_qa
 		global $config, $db, $user;
 
 		$error = '';
-		
+
 		if (!sizeof($this->question_ids))
 		{
 			return false;
 		}
-		
+
 		if (!$this->confirm_id)
 		{
 			$error = $user->lang['CONFIRM_QUESTION_WRONG'];
@@ -434,7 +434,7 @@ class phpbb_captcha_qa
 	function reselect_question()
 	{
 		global $db, $user;
-		
+
 		if (!sizeof($this->question_ids))
 		{
 			return false;
@@ -482,8 +482,8 @@ class phpbb_captcha_qa
 		global $db, $user;
 
 		$sql = 'SELECT confirm_id
-			FROM ' . CAPTCHA_QA_CONFIRM_TABLE . " 
-			WHERE 
+			FROM ' . CAPTCHA_QA_CONFIRM_TABLE . "
+			WHERE
 				session_id = '" . $db->sql_escape($user->session_id) . "'
 				AND lang_iso = '" . $db->sql_escape($this->question_lang) . "'
 				AND confirm_type = " . $this->type;
@@ -505,7 +505,7 @@ class phpbb_captcha_qa
 	function load_answer()
 	{
 		global $db, $user;
-		
+
 		if (!strlen($this->confirm_id) || !sizeof($this->question_ids))
 		{
 			return false;
@@ -990,9 +990,9 @@ class phpbb_captcha_qa
 
 		return $langs;
 	}
-	
-	
-	
+
+
+
 	/**
 	*  See if there is a question other than the one we have
 	*/
diff --git a/phpBB/includes/captcha/plugins/phpbb_recaptcha_plugin.php b/phpBB/includes/captcha/plugins/phpbb_recaptcha_plugin.php
index 0f0bfc4156..dad39867dc 100644
--- a/phpBB/includes/captcha/plugins/phpbb_recaptcha_plugin.php
+++ b/phpBB/includes/captcha/plugins/phpbb_recaptcha_plugin.php
@@ -16,7 +16,7 @@ if (!defined('IN_PHPBB'))
 	exit;
 }
 
-if (!class_exists('phpbb_default_captcha'))
+if (!class_exists('phpbb_default_captcha', false))
 {
 	// we need the classic captcha code for tracking solutions and attempts
 	include($phpbb_root_path . 'includes/captcha/plugins/captcha_abstract.' . $phpEx);
diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 3f097f171f..d88960ff1d 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -2840,7 +2840,7 @@ function login_box($redirect = '', $l_explain = '', $l_success = '', $admin = fa
 {
 	global $db, $user, $template, $auth, $phpEx, $phpbb_root_path, $config;
 
-	if (!class_exists('phpbb_captcha_factory'))
+	if (!class_exists('phpbb_captcha_factory', false))
 	{
 		include($phpbb_root_path . 'includes/captcha/captcha_factory.' . $phpEx);
 	}
diff --git a/phpBB/includes/session.php b/phpBB/includes/session.php
index 37c62c130c..ec7d1e149b 100644
--- a/phpBB/includes/session.php
+++ b/phpBB/includes/session.php
@@ -983,7 +983,7 @@ class session
 			}
 
 			// only called from CRON; should be a safe workaround until the infrastructure gets going
-			if (!class_exists('phpbb_captcha_factory'))
+			if (!class_exists('phpbb_captcha_factory', false))
 			{
 				include($phpbb_root_path . "includes/captcha/captcha_factory." . $phpEx);
 			}
diff --git a/phpBB/install/index.php b/phpBB/install/index.php
index eb51ca5fb2..03b19d1c12 100644
--- a/phpBB/install/index.php
+++ b/phpBB/install/index.php
@@ -152,6 +152,7 @@ else
 @ini_set('memory_limit', $mem_limit);
 
 // Include essential scripts
+require($phpbb_root_path . 'includes/class_loader.' . $phpEx);
 require($phpbb_root_path . 'includes/functions.' . $phpEx);
 
 if (file_exists($phpbb_root_path . 'includes/functions_content.' . $phpEx))
@@ -168,6 +169,9 @@ include($phpbb_root_path . 'includes/functions_admin.' . $phpEx);
 include($phpbb_root_path . 'includes/utf/utf_tools.' . $phpEx);
 require($phpbb_root_path . 'includes/functions_install.' . $phpEx);
 
+$class_loader = new phpbb_class_loader($phpbb_root_path, '.' . $phpEx);
+$class_loader->register();
+
 // Try and load an appropriate language if required
 $language = basename(request_var('language', ''));