Exception Handling in a Windows Forms Application

I'm doing a program for serial communications. To centralize the process of access to serial, created a class.

I am having problem when an exception is lançanda within the class leaves the locked program.

example: When trying aberir the serial port, can give error and the system is at that point to burst memory.

How should I handle errors? Put try and catch? Add another routine?

Error point:

portSerial.Open();  

Program

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using PortSerial.Lib;

namespace ProgramPortSerial
{
    public partial class Form1 : Form    {

        public static LibPortaSerial portSerial = new LibPortSerial();

        public Form1()
        {
            InitializeComponent();

            portSerial.LineReceived += new LineReceivedEventHandler(sp1_LineReceived);
            portSerial.Init(
                ref cmbPortas,
                ref cmbVelocidade,
                ref cmbBitsDeDados,
                ref cmbPariedade,
                ref cmbBitsDeParada,                
                ref cmbControleDeFluxo);            
        }

        void sp1_LineReceived(object sender, LineReceivedEventArgs Args)
        {
            // Tem que ser em uma nova thread para não travar
            Invoke(new Action(() =>
            {
                memDadosRecebidos.Text += "\r\n" + Args.Resposta;
            }));
        }

        private void btnAbrirPorta_Click(object sender, EventArgs e)
        {
            portSerial.Open();            
        }
    }
}

Class PortSerial

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO.Ports;
using System.Windows.Forms;

namespace PortSerial.Lib
{

    public class LibPortSerial : IDisposable
    {
        public SerialPort portSerial;        

        public LibPortSerial()
        {
            portSerial = new SerialPort();
        }

        public void Dispose()
        {
            if (portSerial != null)
                portSerial.Dispose();
        }


        public void Open(
            string port, 
            int veloc,
            int bitsData,
            string pariedade,
            string bitsStop,
            string control)
        {
            portSerial.PortName = port;
            portSerial.BaudRate = veloc;
            portSerial.DataBits = bitsData;
            portSerial.Parity = SetPariedade(pariedade);
            portSerial.StopBits = SetBitsStop(bitsStop);
            portSerial.Handshake = Setcontrol(control); 
            portSerial.Open();  // ==>  Erro this point
        }       
    }
}