Ok so heres my code from this section:

var Cam : Camera;
public var distanceaway;

function Start()
{
    distanceaway = 0;
}

function OnGUI()
{
        GUI.Label (Rect (10, 20, 100, 20), "distance: "+ distanceaway);
}

function Update()
{
    var ray = Cam.ScreenPointToRay (Input.mousePosition); 
    var hit : RaycastHit; 
    if (Physics.Raycast (ray, hit, 1000)) 
    { 
        distanceaway = hit.distance;    
    }
}

When i run it occasionally it will display the distance but most of the time nothing is displayed after "distance: " just every now and then when scanning the environment itll flash up the distance. Any one got any ideas?