--- JavaInvoker.java	2009-04-20 21:54:22.000000000 +0900
+++ JavaInvoker.java.new	2009-06-12 11:00:01.000000000 +0900
@@ -466,6 +466,9 @@
       if (i < args.length && args[i] != null) {
         Value arg = args[i].toValue();
 
+        if (arg instanceof Var)
+          arg = arg.toValue();
+
         int argCost = marshal.getMarshalingCost(arg);
 
         cost = Math.max(argCost + cost, cost);