Fix for issue #1293

Author: meefik

lib/utils.js

@@ -119,7 +119,11 @@ var toError = function(error) {
     : [];
 
   for(var i = 0; i < keys.length; i++) {
-    e[keys[i]] = error[keys[i]];
+    try {
+      e[keys[i]] = error[keys[i]];
+    } catch(err) {
+      // continue
+    }
   }
 
   return e;