diff --git a/adapter/require.src.js b/adapter/require.src.js
index ce2c65bdb..96902bbe1 100644
--- a/adapter/require.src.js
+++ b/adapter/require.src.js
@@ -4,7 +4,13 @@
 
 var load_original = window.requirejs.load;
 requirejs.load = function (context, moduleName, url) {
-  return load_original.call(this, context, moduleName, url + '?' + __testacular__.files[url]);
+  if (__testacular__.files.hasOwnProperty(url)) {
+    url = url + '?' + __testacular__.files[url];
+  } else {
+    console.error('There is no timestamp for ' + url + '!');
+  }
+
+  return load_original.call(this, context, moduleName, url);
 };
 
 require.config({