Script does not behave the way it should?

Hallo. I have been trying to fix the problem for some time, but I simply can not. The point is to enable the player to navigate around a 3 point room, but it just does not behave in a logical manner. Could anyone please help me with this?

I know that this is a large code, but you can ignore a large part of it, which is marked.

 // Variable declarations.
 
 var room = 1;
 var inroom = 1;
 var roomfront : Transform;
 var roomsfront : GameObject;
 var roommed : Transform;
 var roomsmed : GameObject;
 var roomback : Transform;
 var roomsback : GameObject;
 var piano : Transform;
 var walltexture: Material [];
 var walltexturetwo: Material [];
 var MainCamera : Transform;
 var MainCameraOb : GameObject;
 var MovementOfCam = 0;
 static var InWhatPlace = 0;
 var cameraStart : Vector3;
 var cameraAngles: Vector3;
 var cameraPosOne: Vector3;
 var cameraPosTwo: Vector3;
 
 function Update () 
 {
     // You can ingnore the code from here........................................................................
     // This was made some time ago for testing in an infinite map loop.
     
     if (Input.GetKeyDown("space") && inroom == 1) 
     {
         roomsfront.renderer.materials [0] = walltexture[(Random.Range(1, 4))];
         roomsmed.renderer.materials [2]= walltexturetwo[(Random.Range(1, 8))];
         roomback.position = Vector3 (-29.91534, 9.142463, (-94.81549));
         MainCamera.position = Vector3 (-25.54817, 14.8314, (-72.66501 + 7.72372));
         piano.position = Vector3 (-32.32533, 10.80438, -72.66501);
         inroom = 2;
     }
     else if (Input.GetKeyDown ("space") && inroom == 2)
     {
         roomsback.renderer.materials [0]= walltexture[(Random.Range(1, 4))];
         roomsmed.renderer.materials [2]= walltexturetwo[(Random.Range(1, 8))];
         MainCamera.position = Vector3 (-25.54817, 14.8314, (-94.81549 + 7.72372));
         piano.position = Vector3 (-32.32533, 10.80438, (-94.81549));
         roommed.position = Vector3 (-29.91534, 9.142463, (-116.96597));
         inroom = 3;
     }
     else if (Input.GetKeyDown("space") && inroom == 3)
     {
         roomsmed.renderer.materials [0]= walltexture[(Random.Range(1, 4))];
         roomsmed.renderer.materials [2]= walltexturetwo[(Random.Range(0, 8))];
         MainCamera.position = Vector3 (-25.54817, 14.8314, (-50.51353 + 7.72372));
         roomfront.position = Vector3 (-29.91534, 9.142463, -72.66501);    
         roommed.position = Vector3 (-29.91534, 9.142463, -50.51353);
         roomback.position = Vector3 (-29.91534, 9.142463, -28.36128);
         piano.position = Vector3 (-32.32533, 10.80438, -50.51353);
         inroom = 1;
     }
     // To here...................................................................................................
     //There are arrows in the scene, and they return 'Arrows.ToMoveTheCam' 1 or 2. 1 for the Keypad area and 2 for the Piano area.
     // There is also a keypad button, 'cancel', which returns ButtonPressed = 10. Otherwise these are simple key presses.
     
     if (((Input.GetKeyDown("a") && InWhatPlace == 1) || (Input.GetKeyDown("a") && InWhatPlace == 2)) || (KeyOfPad.ButtonPressed  == 10))
     {
         KeyOfPad.ButtonPressed  == 0;
         InWhatPlace = 0;
         iTween.MoveTo(MainCameraOb,Vector3(-24.07,13.57,-43.53),5);
         iTween.RotateTo(MainCameraOb, Vector3(19.01, -142.5, 0), 7);
     }
     if ((Arrows.ToMoveTheCam  == 1) || (Input.GetKeyDown("a") && InWhatPlace == 0) || (Input.GetKeyDown("a") && InWhatPlace == 2))
     {
         InWhatPlace = 1;
         iTween.MoveTo(MainCameraOb,Vector3(-28.94,12.33,-59.96),5);
         iTween.RotateTo(MainCameraOb, Vector3(0, 180, 0), 7);
         Arrows.ToMoveTheCam = 0;
     }
     if ((Arrows.ToMoveTheCam  == 2) || (Input.GetKeyDown("d") && InWhatPlace == 1) || (Input.GetKeyDown("d") && InWhatPlace == 0))
     {
         InWhatPlace = 2;
         iTween.MoveTo(MainCameraOb,Vector3(-28.40594,12.76859,-49.80258),5);
         iTween.RotateTo(MainCameraOb,Vector3(59.25, -90, 0), 6);
         Arrows.ToMoveTheCam = 0;}
     }
     // Give the error 4 times.
     //UnassignedReferenceException: The variable MainCameraOb of 'MainScript' has not been assigned.
     //You probably need to assign the MainCameraOb variable of the MainScript script in the inspector.
     //iTween.Launch (UnityEngine.GameObject target, System.Collections.Hashtable args) (at Assets/Plugins/iTween.cs:6740)
     //iTween.MoveTo (UnityEngine.GameObject target, System.Collections.Hashtable args) (at Assets/Plugins/iTween.cs:1448)
     //iTween.MoveTo (UnityEngine.GameObject target, Vector3 position, Single time) (at Assets/Plugins/iTween.cs:1347)
     //MainScript.Update () (at Assets/Other/MainScript.js:152)