You didn’t provide a line number to say where the error occured.
However, PlayerHealth is a class, which you cannot set to an integer and you have not defined.
public class NewBehaviourScript : MonoBehaviour {
public var Health = 100;
void Start () {
health = 100;
}
void Update () {
if (Health <= 0) {
Application.LoadLevel ("GameOver");
}
}
}
Do some tutorials to get a better understanding of how to use classes.