material failing to render

i made thois script but it doesnt allow a texture to be added on how do i fix this?

Code (csharp):

1. var nxtlvl : boolean = false;
2. function React ()
3. {
4.     nxtlvl = true;
5. }
6. function Update ()
7. {
8.     if(nxtlvl)
9.     {
10.     gameObject.AddComponent(MeshRenderer);
11.        
12.     }
13. }