StreamWriter problems in Unity 5?

I just upgraded to Unity 5 and imported my project to it. Everything works good except I can´t get StreamWriter to function properly. It all worked just fine before, but now it seems like it won´t create the file/save the file. This is my code :

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 using System.Text;
 using System.Xml;
 using System.Xml.Serialization;
 using System.IO;
 
 
 
 public class WriteToXML : MonoBehaviour
 {    
 
     public string textInput;
     public string imagePath;
 
     public GameObject GameManager;
     public GameObject TakeImage;
 
     private GetText getText;
     private TakeImage takeImage;
 
     XmlDocument xmlFile;
 
 
     string pathTilXMLFil;
 
     void Start(){
 
         xmlFile = new XmlDocument();
         getText = GameManager.GetComponent<GetText>();
         takeImage = TakeImage.GetComponent<TakeImage>();
 
         pathTilXMLFil = Application.persistentDataPath + "/oppgaveliste.txt";
 
     }
 
     void Update(){
 
         textInput = getText.textInput;
         imagePath = takeImage.imagePath;
 
 
     }
 
     public void OnMouseDown(){
 
         if(imagePath != null && textInput != null){
 
         WriteToXml ();
 
         }else{
 
             Debug.Log("Du mangler bildet eller tekst!");
 
         }
     }
     
     public void WriteToXml()
     {
 
 
         if(File.Exists(pathTilXMLFil))
         {
         
             xmlFile.Load(pathTilXMLFil);
             Debug.Log ("JEG FANT FILEN!!!!!!!!");
             XmlElement fileRoot = xmlFile.DocumentElement;
             Debug.Log (fileRoot + " funnet");
             XmlElement oppgave = xmlFile.CreateElement("oppgave"); 
             
             XmlElement descriptionNode = xmlFile.CreateElement("beskrivelse"); 
             descriptionNode.InnerText = textInput; 
             
             XmlElement picturePath = xmlFile.CreateElement("bildefil"); 
             picturePath.InnerText = imagePath; 
 
             fileRoot.AppendChild(oppgave);
             oppgave.AppendChild(descriptionNode); 
             oppgave.AppendChild(picturePath); 
             xmlFile.Save(pathTilXMLFil); 
 
 
 
         }else if(!File.Exists(pathTilXMLFil)){
 
         
             Debug.Log ("FINNER IKKE FILEN!!!!");
                 using (StreamWriter sw = File.CreateText(pathTilXMLFil)) 
                 {
                     sw.WriteLine("<oppgaveliste>");
                     sw.WriteLine("<oppgave>");
                     sw.WriteLine("<beskrivelse>" + textInput + "</beskrivelse>");
                     sw.WriteLine("<bildefil>" +  imagePath + "</bildefil>");
                     sw.WriteLine("</oppgave>");
                     sw.WriteLine("</oppgaveliste>");
                 }    
 
         }
     }
 
     
 }

Every time I run "WriteToXML" it goes to !File.Exists(pathTilXMLFil and creates a new file. If I restart the app on iOS, the file is not there at all. So I figure this is something with StreamWriter. Why does has it stopped working? Any ideas?