Problema com ireport , alguem poderia me ajudar?

package relatorio;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.HashMap;
import org.gjt.mm.mysql.Driver;


import net.sf.jasperreports.engine.*;
import net.sf.jasperreports.view.*;

public class testando {


	@SuppressWarnings({ "unchecked", "deprecation" })
	public static void main(String[] args) throws SQLException {
    	Connection con =  null;
		try {
			DriverManager.registerDriver(new Driver());
			con = DriverManager.getConnection("jdbc:mysql://localhost:3306/sisordem", "usuario", "senha");
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

		HashMap parametro = new HashMap();
		parametro.put("PAULO", 1111);
        try {
            //caminho onde esta o relatorio
            JasperReport jr = JasperManager.loadReport("./relatorio/Ordem.jasper");//.compileReport(design);
            JasperPrint impressao = JasperManager.fillReport(jr,parametro,con);
            JasperViewer jrviewer = new JasperViewer(impressao,false);
            jrviewer.setTitle("Ordem de Compra");
            jrviewer.setVisible(true);
        }catch (Exception erro) {
        	erro.printStackTrace();
           System.out.println(erro.getMessage());
        }
 }	
}