diff --git a/system/core/Loader.php b/system/core/Loader.php
index 49bd641..70a6b6f 100644
--- a/system/core/Loader.php
+++ b/system/core/Loader.php
@@ -955,7 +955,7 @@
 		// Is this a class extension request?
 		if (file_exists($subclass))
 		{
-			$baseclass = BASEPATH.'libraries/'.$class.'.php';
+			$baseclass = BASEPATH.'libraries/'.$subdir.$class.'.php';
 
 			if ( ! file_exists($baseclass))
 			{