diff --git a/phpBB/includes/extension/manager.php b/phpBB/includes/extension/manager.php
index b94379141c..6f1c885ea9 100644
--- a/phpBB/includes/extension/manager.php
+++ b/phpBB/includes/extension/manager.php
@@ -437,7 +437,7 @@ class phpbb_extension_manager
 	*/
 	public function available($name)
 	{
-		return file_exists($this->phpbb_root_path . "ext/$name/");
+		return file_exists($this->get_extension_path($name, true));
 	}
 
 	/**
diff --git a/phpBB/index.php b/phpBB/index.php
index 575134f6b1..e6a472ce31 100644
--- a/phpBB/index.php
+++ b/phpBB/index.php
@@ -28,7 +28,7 @@ $user->setup('viewforum');
 if ($ext = $request->variable('ext', ''))
 {
 	// The class to load
-	$class = "phpbb_ext_{$ext}_controller";
+	$class = 'phpbb_ext_' . str_replace('/', '_', $name) . '_controller';
 
 	// Make sure the specified extension is enabled
 	// and that it has a controller class