It seems you are using a 2 dimensions array.
Nevertheless, you never set the dimension of your array to accept this.
At some point, at the very beginning of your game, you need to set the size of your LevelArray object to be width 12 (as you have 12 icons of levels) and height 2 (as you have the number of stars sitting in LevelArray.At(X,0) and the status in LevelArray.At(X,1)).
You also need to modify event 4 in "Global" as it is setting a value in a one dimension array instead of a 2 dimensions array.
Modify the condition :
Modify the action :
LevelArray: Set value at (SelectedLevel, 0) to CollectedStar
This should help making everything related to your array work as long as you are in your game's execution.
Capx corrected in R266