Unity 5 C# script to write to a binary data file- getting a null reference exception and a IOException: sharing violation

Hoping for some help here -- pulled enough hair I am crying "Uncle"

I keep getting two errors; neither of which I seem to be able to resolve myself.

First is a warning about a Null Reference Exception error on the fourth line under ToBinaryDataFile() ("gsaver.NumberPlayers = dataManager.Load("NUMBEROFPLAYERSPLAYING").ToString();"). http://prntscr.com/95v5eq. I also get a IOException:Sharing violation http://prntscr.com/95v6lz.

A file is created, but it appears to be of zero length and have nothing inside.

I know all the routines function with the exception of ToBinaryDataFile() and FromBinaryDataFile().

I left the others included mostly as an aide to others that might like to see how I did those (and in case they have some impact somehow).

 using UnityEngine;
 using System.Collections;
 using System;
 using System.Runtime.Serialization;
 using System.Runtime.Serialization.Formatters.Binary;
 using System.IO;
 
 [Serializable]
 public class GameInformation : MonoBehaviour
 {
     public static string NumberPlayers { get; set; }
     public static string CurrentPlayer { get; set; }
     public static string CurrentPlayerPhase { get; set; }
 
     void Awake()
     {
         DontDestroyOnLoad(transform.gameObject);
     }
 }
 
 // Added the class below as I could not seem to get the static version above to work;  so for purposes of writing to a file I use this redundent non-static class.
 [Serializable]
 public class SGameInformation
 {
     public string NumberPlayers;
     public string CurrentPlayer;
     public string CurrentPlayerPhase;
 }
 
 public class SaveInformation
 {
     public static void ToPreferences()
     {
         PlayerPrefs.SetString("NUMBEROFPLAYERSPLAYING", GameInformation.NumberPlayers);
         PlayerPrefs.SetString("CURRENTPLAYER", GameInformation.CurrentPlayer);
         PlayerPrefs.SetString("CURRENTPLAYERPHASE", GameInformation.CurrentPlayerPhase);
     }
 
     public static void ToBinaryDataFile()
     {
         BinaryFormatter binary = new BinaryFormatter();
         FileStream fStream = File.Create(Application.persistentDataPath + "/saveFile.hag");
         SGameInformation gsaver = new SGameInformation() as SGameInformation;
         gsaver.NumberPlayers = dataManager.Load("NUMBEROFPLAYERSPLAYING").ToString();
         gsaver.CurrentPlayer = dataManager.Load("CURRENTPLAYER").ToString();
         gsaver.CurrentPlayerPhase = dataManager.Load("CURRENTPLAYERPHASE").ToString();
 
         //Tried with and without the following line -- another thread suggested it.
         //Environment.SetEnvironmentVariable("MONO_REFLECTION_SERIALIZER", "yes");
         binary.Serialize(fStream, gsaver);
         fStream.Close();
     }
 }
 
 public class LoadInformation
 {
     public static void FromPreferences()
     {
         GameInformation.NumberPlayers = PlayerPrefs.GetString("NUMBEROFPLAYERSPLAYING", "Two");
         GameInformation.CurrentPlayer = PlayerPrefs.GetString("CURRENTPLAYER", "1");
         GameInformation.CurrentPlayer = PlayerPrefs.GetString("CURRENTPLAYERPHASE", "1");
     }
 
     public static void FromBinaryDataFile()
     {
         if (File.Exists(Application.persistentDataPath + "/saveFile.hag"))
         {
             BinaryFormatter binary = new BinaryFormatter();
             FileStream fStream = File.Open(Application.persistentDataPath + "/saveFile.hag", FileMode.Open);
             var gloader = (SGameInformation)binary.Deserialize(fStream) as SGameInformation;
             fStream.Close();
 
             dataManager.Save("NUMBEROFPLAYINGSPLAYING",gloader.NumberPlayers);
             dataManager.Save("CURRENTPLAYER", gloader.CurrentPlayer);
             dataManager.Save("CURRENTPLAYERPHASE", gloader.CurrentPlayerPhase);
         }
     }
 }
 
     public class dataManager
 {
     public static BinaryFormatter binaryFormatter = new BinaryFormatter();
 
     public static void Save (string saveTag, object obj)
     {
         MemoryStream memoryStream = new MemoryStream();
         binaryFormatter.Serialize(memoryStream, obj);
         string temp = System.Convert.ToBase64String(memoryStream.ToArray());
         PlayerPrefs.SetString(saveTag, temp);
     }
 
     public static object Load(string saveTag)
     {
         string temp = PlayerPrefs.GetString(saveTag);
         if (temp == string.Empty)
         {
             return null;
         }
         MemoryStream memoryStream = new MemoryStream(System.Convert.FromBase64String(temp));
         return binaryFormatter.Deserialize(memoryStream);
     }
 }

Would appreciate responses that resolve the above code. I like how I have it organized -- if only it worked(!).