Removed closing PHP tags, replaced with a comment block identifying the end of the file
diff --git a/system/libraries/Controller.php b/system/libraries/Controller.php
index 4957fc3..1a1e3df 100644
--- a/system/libraries/Controller.php
+++ b/system/libraries/Controller.php
@@ -121,4 +121,6 @@
 

 }

 // END _Controller class

-?>
\ No newline at end of file
+
+/* End of file Controller.php */
+/* Location: ./system/libraries/Controller.php */
\ No newline at end of file