why the wheels moves to the wrong position when i click play. basicvehcontrols.cs

GetComponent().centerOfMass = new Vector3(COM.transform.localPosition.x transform.localScale.x, COM.transform.localPosition.y transform.localScale.y, COM.transform.localPosition.z * transform.localScale.z); fix error please object is a not a refence I to a instance object. nullreferenceexception