Interactions between scripts when using #pragma strict or on Android

Usually when I want a script to interact with another script I do something like this:

     #pragma strict
 
     var otherScript : MonoBehaviour;
     
     function Start()
     {
     otherScript = gameObject.GetComponent(Script);
     
     otherScript.variable = 1.0;
     otherScript.Momo();
     }

And then Unity will freak out about 'variable' and 'Momo()' not being a member of MonoBehaviour, when this totally works and is very convenient normally (when not using #pragma strict or not building for Android). How am I supposed to do interactions between scripts otherwise? I'd use SendMessage, but it seems slow and cumbersome to use for everything.