I'm trying to make a graph with WebChart Control which I downloaded, But i receive this error.

System.Application:Error while saving the file: ---> System.OverflowException: Overflow error.
at WebChart.ChartEngine.GenerateBitmap()
at WebChart.ChartEngine.SaveToFile(String filename, ImageFormat format)
--- End of inner exception stack trace ---
at WebChart.ChartEngine.SaveToFile(String filename, ImageFormat format)