i have a problem with mouse scroll...it was reported to me that mouse scroll on macs does not work, in fact it works for some time then it stucks...can somebody verify this to me?

here is the link to the build: http://bookjungle.com/TESTS/scroll.html

also it seems that it does not calculate properly, in the Input settings i have sensitivity set to 0.25 but radius updates in 0.1 increments. is there efficient way to make sure values are correct and in appropriate format?

here is the code:

var radius : float=2.0;

function OnGUI()
{

    //GET MOUSE SCROLL WHEEL AXIS VALUE (RANGE -0.5 TO 0.5)
    var scroll : float=Input.GetAxis("Mouse ScrollWheel");  
    Debug.Log(scroll.ToString());

    //CALCULATE RADIUS BASED ON MOUSE SCROLL WHEEL AXIS
    radius+=scroll*0.1;

    //LIMIT RADIUS      
    if(radius>=4.5){

        radius=4.5;

    } else if(radius<=0.0){

        radius=0.0;

    }

    //DISPLAY VALUES 
    GUI.Label(Rect(5,5,250,20),"Mouse ScrollWheel Axis: " + scroll.ToString());
    GUI.Label(Rect(5,20,250,20),"Radius: " + radius.ToString());

}