Save, Load script problem

Questions & Answers
1

To start with. Im kinda new to scripting so I tryed to make save/load system for my game.
Because I didnt know how to make it, I watched this video, and copyed most of it and adjusted for my needs
The code is taken from this unity live tutorial session “http://unity3d.com/learn/tutorials/modules/beginner/live-training-archive/persistence-data-saving-loading” And I need help to fix this error I get.

The error "InvalidCastException: Cannot cast from source type to destination type
LevelLoad.Load () (at Assets/Scripts/LevelLoad.cs:69)

This is the Load sctipt.
To see where is the “error” Skip to the //Shows error here

using UnityEngine;
using System.Collections;
using System;
using System.Runtime.Serialization.Formatters.Binary;
using System.IO;

public class LevelLoad : MonoBehaviour {
	private int CHDoneNR;
	private GameObject Box;

	void Awake ()
	{
		Load ();
	}

	void Start()
	{
		switch (CHDoneNR) {
             //Deleted Switch code to shorten the question.
		}
		Debug.Log (CHDoneNR);
	}

	public void Load()
	{
		if (File.Exists (Application.persistentDataPath + "/playerinfo.dat"))
		{
			BinaryFormatter bf = new BinaryFormatter();
			FileStream file = File.Open(Application.persistentDataPath + "/playerinfo.dat", FileMode.Open);
			***//Shows error here***
			PlayerData data = (PlayerData)bf.Deserialize(file);
			file.Close();
			CHDoneNR = data.LevelNR;
		}
	}
	
}
[Serializable]	
class PlayerData
{
	public int LevelNR;
}

This is the Save script

It seems that Save works fine, and is actualy saveing the file, but still I will add it here.

using UnityEngine;
using System.Collections;
using System;
using System.Runtime.Serialization.Formatters.Binary;
using System.IO;

public class LevelSave : MonoBehaviour {
	public int CHDoneNR;

	void OnGUI() {
		if (GUI.Button (new Rect (10, 10, 100, 30), "Save")) {
			Save ();
				}
	}

	public void Save()
	{
		BinaryFormatter bf = new BinaryFormatter ();
		FileStream file = File.Create (Application.persistentDataPath + "/playerinfo.dat");
		PlayerDataSave data = new PlayerDataSave ();
		data.LevelNR = CHDoneNR;
		bf.Serialize (file, data);
		file.Close ();
	}

}
[Serializable]	
class PlayerDataSave
{
	public int LevelNR;
}
2

Problem is you are trying to save a PlayerDataSave class, and loading it as a PlayerData class.

Try casting back to the original class you saved it with, or saving and loading it with the same class.