C# picking up wrong number of excel rows,errors on null value

I am a novice in C# so please forgive me silly mistakes in my code :P I am having the following error come up whenever I am looping through an Excel file:

Additional information: Cannot perform run time binding on a null reference

I have gathered the problem that it is picking up far too many rows (the Excel file only has 2 rows, ends up finding 6 rows?), and by the time it gets to the 3rd row, the error happens. I have opened the Excel file and deleted as many rows after the 2nd row but it keeps coming up with the same issue. As I am here, I wish to ask the following questions:

1. How do I go about addressing the above error.
2. How do I output all the values on the same row, and when row count changes, go onto the next line in the next file and start writing to that?

.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.OleDb;
using System.IO;
using System.Text.RegularExpressions;
using Excel = Microsoft.Office.Interop.Excel;


namespace KTypeLookUp
{
    public partial class Form1 : Form
    {
        FileStream ostrm;
        StreamWriter writer;
        TextWriter oldOut = Console.Out;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {//Select Input File Button
            String textPath = @"C:\AAAtemp\export.txt";
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = "Excel Files(*.xls)|*.xls|All Files|*.*";
            if (ofd.ShowDialog() == DialogResult.OK)
            {//Read and display Excel file
                string path = ofd.FileName.ToString();

                textBox3.Text = path;
                OleDbConnection conn = new OleDbConnection();
                conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=1\";";

                OleDbCommand command = new OleDbCommand
                (
                      "SELECT * FROM [Sheet1$]", conn
                );
                DataSet dataset = new DataSet();
                OleDbDataAdapter adapter = new OleDbDataAdapter(command);
                adapter.Fill(dataset);

                dataGridView1.DataSource = dataset.Tables[0];

                Excel.Application xlApp = new Excel.Application();
                Excel.Workbook xlWorkbook = xlApp.Workbooks.Open(path);
                Excel._Worksheet xlWorksheet = xlWorkbook.Sheets[1];
                Excel.Range xlRange = xlWorksheet.UsedRange;
                int rowCount = xlRange.Rows.Count;
                int colCount = xlRange.Columns.Count;
                try
                {
                    ostrm = new FileStream(textPath, FileMode.OpenOrCreate, FileAccess.Write);
                    writer = new StreamWriter(ostrm);
                }
                catch (Exception ex)
                {
                    ex.ToString();
                   MessageBox.Show("", "My Application",
                   MessageBoxButtons.OKCancel, MessageBoxIcon.Asterisk);
                    return;
                }
                for (int i = 1; i <= rowCount; i++)
                {
                    for (int j = 1; j <= colCount; j++)
                    {
                        Console.SetOut(writer);
                        Console.WriteLine(xlRange.Cells[i, j].Value2.ToString());
                    }
                }
                writer.Close();
                ostrm.Close();
                MessageBox.Show("Text file created", "My Application",
                MessageBoxButtons.OKCancel, MessageBoxIcon.Asterisk); 
            }   
        }

        private void textBox3_TextChanged(object sender, EventArgs e)
        {//Text box to display path
            textBox3.ReadOnly = true;
        }  
    }
}