Text from Resources, single script, multiple scenes

[jcmiguel]

I am confused with a NullReferenceException error. I have a script that populates a label from Resource .txt  files. The script runs on different scenes and modifies the text as one chooses a collider. It works flawless the first time you open the scene but if you go back to the main menu and reenters the scene or if you move to a different scene, the error appears. Someone at unity forum suggested that I used Object.DontDestroyOnLoad but seems unlikely to solve my problem

1.  void ChangeFeaturedText(string filename)
2.         {
3.                 //Load text data from resources
4.                 TextAsset toothdata = (TextAsset)Resources.Load(filename, typeof(TextAsset));
5.                 reader = new StringReader(toothdata.text);
6.                
7.                
8.                 //confirm if textdata is valid and read it
9.                 if ( reader == null )
10.                 {
11.                 Debug.Log(filename+".txt not found or not readable");
12.                 }
13.                 else
14.                 {
15.                 // Read each line from the fil+string txt;
16.                         string txt;
17.                         longtext="";
18.             while ( (txt=reader.ReadLine()) != null)
19.             {
20.                         longtext += txt;
21.        
22.                         }
23.                         reader.Close();
24.                         UILabel label = NGUITools.FindInParents<UILabel>(labeltarget);
25.                         Debug.Log (filename+".txt target found");
26.                        
27.                         label.text=longtext;// line where error appears: NullReferenceException: Object reference not set to an instance of an object
28.                                                                 //SelectFeature.ChangeFeaturedText (System.String filename) (at Assets/Scripts/SelectFeature.cs:106)
29.                        
30.                        
31.                         Resources.UnloadAsset (toothdata);
32.  
33.                                
34.                 }
35.  
36.         }

How can I use the same script on different scenes with the ability to move from one to another?
Many thanks

[ArenMook]

So the "label" is null. You never check for it being null. I don't know when this function of yours is executed. Apparently it happens before the label it relies upon is set up.

[jcmiguel]

Solved! I just inserted          
if(label==null)
         {
            Debug.Log ("label is null");
         }
         else...
Thanks