Cannot Save due to file access denied WINDOWS 8 COMPUTER

I have just followed this tutorial however now i come into 2 issue.

the first is that the add on to the save file "/PlayerBuild" i have to manually go make the folder where as in the tutorial it is created on its own.

Second is that the file access is denied, I am using a windows 8 computer and have tried running as admin and turning of my anti virus however it still does not work.

I am trying to save an array so that could be part of the issue? although the array does not through up any errors, someone said that you cannot save gameobject but i was not sure if it was true or not.

Here is the code:

 using UnityEngine;
 using System.Collections;
 using System;
 using System.Runtime.Serialization.Formatters.Binary;
 using System.IO;
 
 public class BuildSaver : MonoBehaviour {
 
     public static BuildSaver save;
 
     public GameObject[] build;
 
     void Awake(){
         if (save == null) {
             DontDestroyOnLoad (gameObject);
             save = this;
         } else if (save != this) {
 
             Destroy (gameObject);
         }
     }
 
 
 
 
     public void Save(){
 
         build = GameObject.FindGameObjectsWithTag ("Block");
 
 
         BinaryFormatter bf = new BinaryFormatter ();
         FileStream file = File.Open(Application.persistentDataPath + "/PlayerBuilds" , FileMode.Open);
 
         BuildData data = new BuildData ();
         data.build = build;
 
         bf.Serialize (file, data);
         file.Close();
     }
 
     public void Load(){
 
         if (File.Exists (Application.persistentDataPath + "/PlayerBuilds")) {
             BinaryFormatter bf = new BinaryFormatter();
             FileStream file = File.Open(Application.persistentDataPath + "/PlayerBuilds", FileMode.Open);
             BuildData data = (BuildData)bf.Deserialize (file);
             file.Close ();
             build = data.build;
         }
 
     }
     }
 
     [Serializable]
     class BuildData{
         
         public GameObject[] build;
 
 
     }