403在使用Hadoop时创建文件.WebHDFSClient，虽然能够在HDFS中创建文件夹

此代码一直工作到创建文件夹，然后无法创建文件并抛出403。我是不是遗漏了一些验证的东西。我是Hadoop的新手，正在尝试学习hdInsight。

    private static void uploadFile()
    {
        //set variables
        string srcFileName = @"./prime/in/integers.txt";
        string destFolderName = @"/prime/in";
        string destFileName = @"integers.txt";
        string outputFolderName= @"/prime/out";
        //connect to hadoop cluster
        Uri myUri = new Uri("http://DXPZN72-LP:50070");
        string userName = "hadoop";
        WebHDFSClient myClient = new WebHDFSClient(myUri, userName);
        //drop destination directory (if exists)
        myClient.DeleteDirectory(destFolderName, true).Wait();
        //create destination directory
        myClient.CreateDirectory(destFolderName).Wait();
        //create outputFolderName directory
        myClient.CreateDirectory(outputFolderName).Wait();
        //load file to destination directory
        var res= myClient.CreateFile(srcFileName,  "/" +destFileName);
        res.Wait();
        //list file contents of destination directory
        Console.WriteLine();
        Console.WriteLine("Contents of " +destFolderName);
        myClient.GetDirectoryStatus(destFolderName).ContinueWith(
             ds => ds.Result.Files.ToList().ForEach(
             f => Console.WriteLine("t" +f.PathSuffix)
             ));
        //keep command window open until user presses enter
        Console.ReadLine();
    }