Export splatmap into png failed?

import System.Collections;
import System.IO;

@MenuItem("Assets/Export Texture") 
static function Apply () { 
var texture : Texture2D = Selection.activeObject as Texture2D; 
if (texture == null) 
{ 
EditorUtility.DisplayDialog("Select Texture", "You Must Select a Texture first!", "Ok"); 
return; 
} 
var bytes = texture.EncodeToPNG(); 
File.WriteAllBytes(Application.dataPath + "/exported_texture.png", bytes); 
} 

^ I use to export the splatmap of my Terrain in unity3d this script (over here)^

But it fails everytime, because i cant see anything on the .png. Its only an empty picture, but if i look in unity3d then there is the png with a picture.

I hope somebody knows whats wrong ._.

Pictures below here:

The “empty” .png :

alt text

2 picture

alt text

Nobody can help me with my problem? -.-