Create an arrow dynamically following the spline

[Trainzland]

I think that have to do with Initializing the complete spline system at start.
Are you sure the splines are fully initialized when you use it?

Code:

 IEnumerator Start() {
          foreach (var Spline in FindObjectsOfType(typeof(CurvySpline)) as CurvySpline[]) {
              while (!Spline.IsInitialized) {
                  yield return null;
              }
          }
      }

You can check this, if you wait a second, then calling your function.
public int frames;

Code:

void Update(){
  frames++;
  if (frames > 100)  run your function to create the arrow.

}

only an idea.