U3DXT Social FacebookPost not Working?

public void PostOnFaceBook()

{
	if (CoreXT.IsDevice) {
		Application.CaptureScreenshot ("ScreenShot.png");
		UIImage tmp = new UIImage (Application.persistentDataPath + "/ScreenShot.png");
		// share
		if(_stringPostOnWtitterAndFaceBook == "")
		{
			_stringPostOnWtitterAndFaceBook = "Post !";
		}
		if(_link == "")
		{
			_link = "http://abc.com";
		}
		if(tmp.IsNil)
		{
			SocialXT.Post (SLRequest.SLServiceTypeFacebook, _stringPostOnWtitterAndFaceBook, GameObject.Find("Logo").GetComponent<GUITexture>().texture as Texture2D, _link, true);
		}else
		{
			SocialXT.Post (SLRequest.SLServiceTypeFacebook, _stringPostOnWtitterAndFaceBook, tmp, _link, true);
			System.IO.File.Delete (Application.persistentDataPath + "/ScreenShot.png");			
			
		}

	} 
}

GameObject.Find(“Logo”).GetComponent().texture is not null.
I’m call thist method from other GameObject. But It not working !. . .

It works only in Device, not even in Simulator