ensured the security lib was loaded in a few calls to xss_clean() in other libraries.  Fixes #35
diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index 3227c37..d7cf236 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -854,7 +854,12 @@
 		}
 
 		$CI =& get_instance();
-
+		
+		if ( ! is_object($CI->security))
+		{
+			$CI->load('security');
+		}
+		
 		return $CI->security->xss_clean($data, TRUE);
 	}