--- a/caps/idl/nsIPrincipal.idl
+++ b/caps/idl/nsIPrincipal.idl
@@ -219,17 +219,17 @@ interface nsIPrincipal : nsISerializable
      *       function.
      *
      *
      * @param uri    The URI about to be loaded.
      * @param report If true, will report a warning to the console service
      *               if the load is not allowed.
      * @throws NS_ERROR_DOM_BAD_URI if the load is not allowed.
      */
-    [noscript] void checkMayLoad(in nsIUri uri, in boolean report);
+    [noscript] void checkMayLoad(in nsIURI uri, in boolean report);
 
     /**
      * The subject name for the certificate.  This actually identifies the
      * subject of the certificate.  This may well not be a string that would
      * mean much to a typical user on its own (e.g. it may have a number of
      * different names all concatenated together with some information on what
      * they mean in between).
      *