On Mouse Enter Problems

Hi guys,
I’m a Unity newbie… And I have a problem with OnMouseEnter() script: it works good when my cursor is in an object near the camera, but it didn’t works if the object is far away. What can i do? Here is my code:

var cursorTexture : Texture2D;
var cursorMode : CursorMode = CursorMode.Auto;
var hotSpot : Vector2 = Vector2.zero;

function OnMouseEnter(){
	Cursor.SetCursor(cursorTexture, hotSpot, cursorMode);   
}

function OnMouseExit(){
    Cursor.SetCursor(null, Vector2.zero, cursorMode);
}

The object has to be in front, and the cursor has to be over the specific object the script is attached to, but distance shouldn’t matter. I ran a quick test just to be sure there was not some limit on the Raycast. I used an object that was 8000 units away from the camera and took just a few pixel of screen space at that distance, and it worked fine. I’m guessing you have an object with some transparency, and the ray is hitting that object first.