diff --git a/promise.js b/promise.js
index cde8183..ae951a7 100644
--- a/promise.js
+++ b/promise.js
@@ -94,8 +94,9 @@ Promise.prototype.put = function(propertyName, value){
 };
 
 Promise.prototype.call = function(functionName /*, args */){
+  var args = Array.prototype.slice.call(arguments, 1);
   return this.then(function(value){
-    return value[functionName].apply(value, Array.prototype.slice.call(arguments, 1));
+    return value[functionName].apply(value, args);
   });
 };
 
@@ -195,7 +196,12 @@ function Deferred(canceller){
     if (!dontThrow) {
       enqueue(function () {
         if (!handled) {
-          throw error;
+          if (typeof(error) === 'string') {
+            throw new Error(error);
+          }
+          else {
+            throw error;
+          }
         }
       });
     }