How to find out what is getting a null reference?
Is the source code available if there is a license?

System.NullReferenceException: Object reference not set to an instance of an object.
 at Infragistics.Controls.Charts.PolarBase.PointAlongLineHelper(Point world, Boolean visibleOnly)
 at Infragistics.Controls.Charts.PolarBase.GetItemIndex(Point world)
 at Infragistics.Controls.Charts.PolarBase.GetItem(Point world)
 at Infragistics.Controls.Charts.Series.PropertyUpdatedOverride(Object sender, String propertyName, Object oldValue, Object newValue)
 at Infragistics.Controls.Charts.MarkerSeries.PropertyUpdatedOverride(Object sender, String propertyName, Object oldValue, Object newValue)
 at Infragistics.Controls.Charts.PolarBase.PropertyUpdatedOverride(Object sender, String propertyName, Object oldValue, Object newValue)
 at Infragistics.Controls.Charts.PolarLineSeries.PropertyUpdatedOverride(Object sender, String propertyName, Object oldValue, Object newValue)
 at Infragistics.Controls.Charts.Series.<.ctor>b__16_1(Object o, PropertyUpdatedEventArgs e)
 at Infragistics.Controls.Charts.PropertyUpdatedEventHandler.Invoke(Object sender, PropertyUpdatedEventArgs e)
 at Infragistics.Controls.SeriesViewer.RaisePropertyChanged(String name, Object oldValue, Object newValue)
 at Infragistics.Controls.Charts.SyncLink.CrosshairNotify(SeriesViewer sender, Point crossHairPoint)
 at Infragistics.Controls.Charts.SeriesViewerInteractionManager.OnContactMoved(SeriesViewer target, Point pt, Boolean isFinger)
 at Infragistics.Controls.SeriesViewerView.OnContactMoved(Point p, Boolean isFinger)
 at Infragistics.Portable.Controls.EventProxy.RaiseOnContactMoved(Point point, Boolean isFinger)
 at Infragistics.Win.DataVisualization.WFEventProxy.Target_MouseMove(Object sender, MouseEventArgs e)
 at System.Windows.Forms.MouseEventHandler.Invoke(Object sender, MouseEventArgs e)
 at System.Windows.Forms.Control.OnMouseMove(MouseEventArgs e)
 at System.Windows.Forms.Control.WmMouseMove(Message& m)
 at System.Windows.Forms.Control.WndProc(Message& m)
 at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)