How do I fix this script?

I have a code that makes my FPS Controller slow down when the input 'Aim' is held. Here's the code...

Code (CSharp):

1. var walkSpeed: float = 7; // regular speed
2. var aimSpeed: float = 3.5; // aiming speed
3. private var chMotor: CharacterMotor;
4. function Start(){
5.      chMotor = GetComponent(CharacterMotor);
6.      var ch:CharacterController = GetComponent(CharacterController);
7. }
8. function Update(){
9.      var speed = walkSpeed;
10.      if (chMotor.grounded && Input.GetButton("Aim")){
11.          speed = aimSpeed;
12.       }
13.       chMotor.movement.maxForwardSpeed.maxBackwardsSpeed.maxSidewaysSpeed = speed; // set max speed
14. }

But, whenever I put it in my scene, I get this error...

MissingFieldException: System.Single.maxBackwardsSpeed
Boo.Lang.Runtime.DynamicDispatching.PropertyDispatcherFactory.FindExtension (IEnumerable`1 candidates)
Boo.Lang.Runtime.DynamicDispatching.PropertyDispatcherFactory.Create (SetOrGet gos)
Boo.Lang.Runtime.DynamicDispatching.PropertyDispatcherFactory.CreateGetter ()
Boo.Lang.Runtime.RuntimeServices.DoCreatePropGetDispatcher (System.Object target, System.Type type, System.String name)
Boo.Lang.Runtime.RuntimeServices.CreatePropGetDispatcher (System.Object target, System.String name)
Boo.Lang.Runtime.RuntimeServices+<GetProperty>c__AnonStorey17.<>m__C ()
Boo.Lang.Runtime.DynamicDispatching.DispatcherCache.Get (Boo.Lang.Runtime.DynamicDispatching.DispatcherKey key, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.String cacheKeyName, System.Type[] cacheKeyTypes, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
Boo.Lang.Runtime.RuntimeServices.GetDispatcher (System.Object target, System.Object[] args, System.String cacheKeyName, Boo.Lang.Runtime.DynamicDispatching.DispatcherFactory factory)
Boo.Lang.Runtime.RuntimeServices.GetProperty (System.Object target, System.String name)
UnityScript.Lang.UnityRuntimeServices.GetProperty (System.Object target, System.String name)

How do I fix it? Thanks!

 

This line

Code (JavaScript):

1. chMotor.movement.maxForwardSpeed.maxBackwardsSpeed.maxSidewaysSpeed = speed; // set max speed
2.  

has to be changed to something like

Code (JavaScript):

1. chMotor.movement.maxForwardSpeed = speed;
2. chMotor.movement.maxBackwardsSpeed = speed;
3. chMotor.movement.maxSidewaysSpeed = speed;
4.  

You could also define a method which does it for you.

 

I didn't try it yet since it's really late, but thanks still. Someone told me to add SidewaySpeed and BackwardsSpeed and that was it. Again, thanks!