diff --git a/Objective-J/evaluate.js b/Objective-J/evaluate.js
index 50a902d63..02e33aaf3 100644
--- a/Objective-J/evaluate.js
+++ b/Objective-J/evaluate.js
@@ -159,7 +159,7 @@ function fragment_evaluate_code(aFragment)
     {
 #if RHINO
         var functionText = "function(){"+GET_CODE(aFragment)+"/**/\n}";
-        if (system.engine === "rhino")
+        if (typeof system !== "undefined" && system.engine === "rhino")
             compiled = Packages.org.mozilla.javascript.Context.getCurrentContext().compileFunction(window, functionText, GET_FILE(aFragment).path, 0, null);
         else
             compiled = eval(functionText);