Set child gameobject active?

How can you set the child of a gameobject active I have tried


But I get the error

NullReferenceException: Object reference not set to an instance of an object
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)
BuildZone.Update () (at Assets/my assets/Scripts/BuildZone.js:24)

the script was attached to the parent of the object I was trying to make active
How can I make the object active?

Transform has no child property, so this should not even compileā€¦

To access children of a Transform, please use:

for (var child : Transform in transform)
    if(....) // check if this is the child you want to activate, by name, tag or anything else

If you have one child only, then of course you can skip the if statement. You can also access a child by its index using GetChild method.