Multiple controls with the same ID 'lebelId1' were found. FindControl requires that controls have unique IDs.

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;
using ControlMethods_BL;
using CheckList_DAL;

namespace CheckList
{
    public partial class Home : System.Web.UI.Page
    {
        static int number = 2;
        ControlMethod controlMethod = new ControlMethod();
        string strConn = connection.cn;
        SqlConnection conn = new SqlConnection();
        SqlCommand cmd;
        //UserRegistrationBL registration = new UserRegistrationBL();
        TaskMaster taskMaster = new TaskMaster();
        SqlDataReader rdr;
        protected void Page_Load(object sender, EventArgs e)
        {
            DataReaderMethod();
        }

        private void DataReaderMethod()
        {
            conn.ConnectionString = strConn;
            string strQuery = "select S.Id, G.GMName, T.CheckPointTaskType, T.CheckRemark, S.TaskDate from tblTaskMasterStatus S, tblTaskMaster T, tblGeneralMaster G where S.TaskId=T.Id and T.ServerId=G.ID";

            cmd = new SqlCommand(strQuery, conn);
            try
            {
                conn.Open();
                rdr = cmd.ExecuteReader();

                while (rdr.Read())
                {                  
                        DynamicControlMethod(rdr);                   
                }
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }

            finally
            {
                conn.Close();
            }
        }

        private void DynamicControlMethod(SqlDataReader rdr)
        {                  
                for (int i = 1; i <number mode="hold" />                {                    
                    Table t = new Table();
                    TableRow row = new TableRow();

                    TableCell cellId = new TableCell();                   
                    cellId.Width = Unit.Pixel(1);
                    Label labelID = new Label();
                    labelID.ID = "lebelId" + i.ToString();
                    labelID.Text = rdr["Id"].ToString();
                    cellId.Controls.Add(labelID);
                    row.Cells.Add(cellId);                   
                    pnlID.Controls.Add(row);

                    TableCell cellGMName = new TableCell();
                    cellId.Width = Unit.Pixel(70);
                    Label lebelGMName = new Label();
                    lebelGMName.ID = "lebelGMName" + i.ToString();
                    lebelGMName.Text = rdr["GMName"].ToString();
                    cellGMName.Controls.Add(lebelGMName);
                    row.Cells.Add(cellGMName);                    
                    pnlServerName.Controls.Add(row);

                    TableCell cellCheckPointTaskType = new TableCell();
                    cellId.Width = Unit.Percentage(10);
                    Label lebelCheckPointTaskType = new Label();
                    lebelCheckPointTaskType.ID = "lebelCheckPointTaskType" + i.ToString();
                    lebelCheckPointTaskType.Text = rdr["CheckPointTaskType"].ToString();
                    cellCheckPointTaskType.Controls.Add(lebelCheckPointTaskType);
                    row.Cells.Add(cellCheckPointTaskType);                    
                    pnlCheckPointTaskType.Controls.Add(row);

                    TableCell cellCheckRemark = new TableCell();
                    cellId.Width = Unit.Percentage(30);
                    Label lebelCheckRemark = new Label();
                    lebelCheckRemark.ID = "lebelCheckRemark" + i.ToString();
                    lebelCheckRemark.Text = rdr["CheckRemark"].ToString();
                    cellCheckRemark.Controls.Add(lebelCheckRemark);
                    row.Cells.Add(cellCheckRemark);                   
                    pnlCheckRemark.Controls.Add(row);
                   
                    TableCell cellSpace = new TableCell();
                    cellId.Width = Unit.Percentage(10);
                    TextBox textboxSpace = new TextBox();
                    textboxSpace.ID = "textboxSpace" + i.ToString();
                    cellSpace.Controls.Add(textboxSpace);
                    row.Cells.Add(cellSpace);                    
                    pnlSpace.Controls.Add(row);

                    TableCell cellComment = new TableCell();
                    cellId.Width = Unit.Percentage(5);
                    CheckBox checkBoxComment = new CheckBox();
                    checkBoxComment.ID = "checkBoxComment" + i.ToString();
                    cellComment.Controls.Add(checkBoxComment);
                    row.Cells.Add(cellComment);                   
                    pnlCheck.Controls.Add(row);

                    TableCell cellRemarks = new TableCell();
                    cellId.Width = Unit.Percentage(10);
                    TextBox remarkTextBox = new TextBox();
                    remarkTextBox.ID = "remarkTextBox" + i.ToString();
                    cellRemarks.Controls.Add(remarkTextBox);
                    row.Cells.Add(cellRemarks);                   
                    pnlRemarks.Controls.Add(row);                
                }            
        }

        public void btnSubmit_Click(object sender, EventArgs e)
        {

            string strCon = ConfigurationManager.ConnectionStrings["RealWorldConnectionString"].ConnectionString;
            SqlConnection con = new SqlConnection(strCon);

            for (int i = 0; i < 1; i++)
            {
                string SpaceData = "textboxSpace" + i.ToString();
                TextBox txt = (TextBox)pnlSpace.FindControl(SpaceData);          
            }               
        }
    }
}