Switching scene problem

`I have created many scenes. two scenes named "GameOver" and "ScreenSetting". in these scenes i have made some texture with script. problem is that when i play this scene then it shows all the textures of scene but when i switch to other scene and come back to these two scene and play then no texture is displayed. whts the problem? sample code is here

 function OnGUI() {
     if(!soundTexture){
             Debug.LogError("Assign a Sound Texture in the inspector.");
             return;
         }
         GUI.DrawTexture(Rect((Screen.width*20)/100,(Screen.height*15)/100,(Screen.width*38)/100,(Screen.height*20)/100), soundTexture);
     if(!vibrateTexture){
             Debug.LogError("Assign a vibrate Texture in the inspector.");
             return;
         }
         GUI.DrawTexture(Rect((Screen.width*21)/100,(Screen.height*43)/100,(Screen.width*38)/100,(Screen.height*20)/100), vibrateTexture);
             
         if(!fastTexture){
             Debug.LogError("Assign a fast Texture in the inspector.");
             return;
         }
         GUI.DrawTexture(Rect((Screen.width*20)/100,(Screen.height*70)/100,(Screen.width*38)/100,(Screen.height*20)/100), fastTexture);
         
         if (GUI.Button(Rect((Screen.width*5)/100,(Screen.height*80)/100,(Screen.width*20)/100,(Screen.height*20)/100),back,testStyle)){
                 Application.LoadLevel("StartScene");
                 Handheld.Vibrate();
                 
             
             }
      }

`

these are the texture which i have defined in setting Scene, when I assign all the texture and play first time then it shows all the texture but when i switch to other scene and come back to setting scene then no texture appears when i play