Fixed a routing bug that occurred when the default route pointed to a subfolder.  Bug report: http://codeigniter.com/bug_tracker/bug/4661/
diff --git a/system/libraries/Router.php b/system/libraries/Router.php
index 4b90b4b..f192379 100644
--- a/system/libraries/Router.php
+++ b/system/libraries/Router.php
@@ -63,7 +63,7 @@
 	 * @return	void

 	 */

 	function _set_routing()

-	{		

+	{

 		// Are query strings enabled in the config file?

 		// If so, we're done since segment based URIs are not used with query strings.

 		if ($this->config->item('enable_query_strings') === TRUE AND isset($_GET[$this->config->item('controller_trigger')]))

@@ -97,16 +97,8 @@
 			{

 				show_error("Unable to determine what should be displayed. A default route has not been specified in the routing file.");

 			}

-		

-			$this->set_class($this->default_controller);

-			$this->set_method('index');

-			$this->_set_request(array($this->default_controller, 'index'));

-			

-			// re-index the routed segments array so it starts with 1 rather than 0

-			$this->uri->_reindex_segments();

-			

-			log_message('debug', "No URI present. Default controller set.");

-			return;

+

+			$this->uri->uri_string = $this->default_controller;

 		}

 		unset($this->routes['default_controller']);