IsolatedStorageException: Could not find a part of the path

I want to be able to save a file into my executable folder. But it doesn't save the file and throws the exception "IsolatedStorageException: Could not find a part of the path..."

When I run this application using the Unity Editor it saves it onto the correct save file which is located on the Asset folder but when I run it in Build it doesn't save it.

Here is the code I have:

 using UnityEngine;
 using System.Collections;
 using System.Xml;
 using System.Xml.Serialization;
 using System.IO;
 using System.Text;  
 using System.Collections.Generic;
 
 public class TrainingData : MonoBehaviour 
 {
     string _FileLocation,_FileName;
     string _data;
 
     UserData iData = new UserData();
     
     // When the EGO is instansiated the Start will trigger 
     // so we setup our initial values for our local members 
     void Start () {
         
         // Where we want to save and load to and from 
         _FileLocation=Application.dataPath; 
         _FileName="SaveData.xml";
     } 
     
     void Update () {}     
     
     public void Save(int userID, int x, int y, int z)
     {
         if (!Load())
             return;
         _data = string.Empty;
 
         bool isUserFound = false;
         foreach (var user in iData._users)
         {
             // Time to creat our XML!             
             if (userID == user.userID)
             {
                 user.userID = userID;
                 user.x = x;
                 user.y = y;
                 user.z = z;
 
                 isUserFound = true;
             }
             //_data += SerializeObject(user);
             
         }
         if (!isUserFound)
         {
             UserData.mUsers newUser = new UserData.mUsers();
             newUser.userID = userID;
             newUser.x = x;
             newUser.y = y;
             newUser.z = z;
             iData._users.Add(newUser);
         }
 
         _data = SerializeObject(iData);
         // This is the final resulting XML from the serialization process 
         CreateXML();
         Debug.Log(_data);          
 
     }
     private bool Load()
     {
         // Load our UserData into myData 
         LoadXML();
         if (_data.ToString() == "")
         {
             return false;
         }
         // notice how I use a reference to type (UserData) here, you need this 
         // so that the returned object is converted into the correct type
         var data = FixData();
         iData._users.Clear();
         var counter = 0;
         foreach (var dataToParse in data)
         {
             counter++;
             if (counter == 1) continue;
 
             if (string.IsNullOrEmpty(dataToParse.Trim())) continue;
             var uData = (UserData)DeserializeObject(dataToParse);
             iData._users.Add(uData._users[0]);
             //var ud = iData._users[iData._users.Count - 1];
             // just a way to show that we loaded in ok
         }        
         return true;
     }
     string[] FixData()
     {
         var dataSplit = _data.Split(new string[] { "<mUsers>", "</mUsers>" }, System.StringSplitOptions.RemoveEmptyEntries);
         dataSplit[0] = dataSplit[0].Replace("<_users>", string.Empty);
         for (var indx = 1; indx < dataSplit.Length; indx++ )
         {
             if (string.IsNullOrEmpty(dataSplit[indx].Trim()) || !dataSplit[indx].Contains("x"))
             {
                 dataSplit[indx] = string.Empty;
                 continue;
             }
 
             dataSplit[indx] = dataSplit[0] + "<_users><mUsers>" + dataSplit[indx] + "</mUsers></_users></UserData>";
             Debug.Log(dataSplit[indx]);
         }
 
         return dataSplit;
     }
     
      
     string UTF8ByteArrayToString(byte[] characters) 
     {      
         UTF8Encoding encoding = new UTF8Encoding(); 
         string constructedString = encoding.GetString(characters); 
         return (constructedString); 
     } 
     
     byte[] StringToUTF8ByteArray(string pXmlString) 
     { 
         UTF8Encoding encoding = new UTF8Encoding(); 
         byte[] byteArray = encoding.GetBytes(pXmlString); 
         return byteArray; 
     } 
 
     //// Here we serialize our UserData object of myData 
     string SerializeObject(UserData userData)
     {
         string XmlizedString = string.Empty;
         
         XmlSerializer xs = new XmlSerializer(typeof(UserData));
         MemoryStream memoryStream = new MemoryStream();
         XmlTextWriter xmlTextWriter = new XmlTextWriter(memoryStream, Encoding.UTF8);
         xs.Serialize(xmlTextWriter, userData);
         memoryStream = (MemoryStream)xmlTextWriter.BaseStream;
 
         XmlizedString = UTF8ByteArrayToString(memoryStream.ToArray());
         //foreach (var user in l_userData)
         //{
             
         //}
         
         return XmlizedString;
     }
 
     // Here we deserialize it back into its original form 
     object DeserializeObject(string pXmlizedString) 
     { 
         XmlSerializer xs = new XmlSerializer(typeof(UserData)); 
         MemoryStream memoryStream = new MemoryStream(StringToUTF8ByteArray(pXmlizedString)); 
         //XmlTextWriter xmlTextWriter = new XmlTextWriter(memoryStream, Encoding.UTF8); 
         return xs.Deserialize(memoryStream); 
     } 
     
     // Finally our save and load methods for the file itself 
     void CreateXML() 
     { 
         StreamWriter writer;
         
         FileInfo t = new FileInfo(_FileLocation+"\\"+ _FileName); 
         if(!t.Exists) 
         { 
             writer = t.CreateText();
         } 
         else 
         { 
             t.Delete(); 
             writer = t.CreateText(); 
         } 
         writer.Write(_data); 
         writer.Close(); 
         Debug.Log("File written."); 
     } 
     
     void LoadXML() 
     {
         StreamReader r = File.OpenText(_FileLocation+"\\"+ _FileName); 
         string _info = r.ReadToEnd(); 
         r.Close(); 
         _data=_info; 
         Debug.Log("File Read"); 
     } 
 } 
 
 // UserData is our custom class that holds our defined objects we want to store in XML format 
 public class UserData 
 {
     public List<mUsers> _users = new List<mUsers>();
 
     public class mUsers
     {
         // We have to define a default instance of the structure    
         public int userID;
         public int x;
         public int y;
         public int z;
     }
     
     // Default constructor doesn't really do anything at the moment 
     public UserData() { } 
 }

Can anyone see what I am missing. I do believe that the problem is that it is not creating the xml file at all, but I am not sure. Thank you in advance.