代码出错，求大神解答
using UnityEngine;
using System.Collections;

public class cubeScript : MonoBehaviour {

// Use this for initialization
void Start () {


}

// Update is called once per frame
void Update () {


}
void OnGUI()
{

  if (GUI.Button(new Rect(440, Screen.height - 25, 65, 23), "Snapshot"))
{
  LoadHelp.UploadPNG(this, "Snapshot", delegate(bool result)
{
  if (result)
  {
  Application.Externaleval_r("alert('ok')");
  }
  }
);
  }
}
}
他说我有错错在 LoadHelp.UploadPNG(this, "Snapshot", delegate(bool result)这行
然后显示是这样的错误Assets/DressingroomExample/cubeScript.cs(22,10): error CS0103: The name `LoadHelp' does not exist in the current context
这是什么问题？

------解决方案--------------------
找不到LoadHelp类，确保是否加入了该类的命名空间引用
------解决方案--------------------
LoadHelp在哪里定义的
添加引用了么