UCE0001 ';' expected. Insert a semicolon at the end.

#pragma strict

var TheDamage : int = 50;
var Distance : float;

function update ()
{
	if (Input.GetButtonDown("Fire1"))
	{
		var hit : Raycast hit;
		if (Physics.Raycast (Transform.posistion, transform.TransformDirection(Vector3.forward), hit))
		{
			Distance = hit.distance;
			hit.transform.SendMessage("ApplyDamage", TheDamage, SendMessageOptions.DontRequireReceiver);
		}
	}
}

var hit : Raycast hit;

should be

var hit : Raycast;