问萌新问题，为什么索引超出了数组界限？

private void button1_Click(object sender, EventArgs e)
        {
           // string word = textBox1.Text;
           // string word1;

            //指定Excel文件的路径
            string file_name = @"D:\log\log1.xls";
            //拼装一个连接字符串
           // string strConn = "Provider=Microsoft.Jet.Oledb.4.0;Data Source=" + file_name + ";Extended Properties='Excel 8.0;HDR=YES;IMEX=1;'";
            string strConn = "Provider=Microsoft.ACE.OLEDB.12.0;" + "data source=" + file_name + ";Extended Properties='Excel 8.0;HDR=Yes;IMEX=1'";
            //声明一个连接对象
            OleDbConnection conn = new OleDbConnection(strConn);
            //将查询结果放入数据适配器中
            OleDbDataAdapter adp = new OleDbDataAdapter("select * from [Sheet1$] where cellid='" + textBox1.Text.ToString() + "'", conn);
            //声明一个DataSet
            DataSet ds = new DataSet();
            //将查询出的记录集从数据适配器中放到DataSet中
            adp.Fill(ds);
            //数据绑定
            DataTable table = ds.Tables[0];
            // dataGridView1.DataSource = ds.Tables[0];
            DataRow[] rows = table.Select();
            string num;
            num = rows[0].ItemArray[1].ToString();//这里抛异常
            conn.Close();   


            System.Diagnostics.Process process = new System.Diagnostics.Process();
            process.StartInfo.FileName = "G:\\"+num+".jpg";      
            process.StartInfo.Arguments = "rundll32.exe C://WINDOWS//system32//shimgvw.dll";    
            process.StartInfo.UseShellExecute = true;    
            process.Start();
        }