crystal report page navigation not work well

private void ConfigureCrystalReports()
    {
        try
        {
            con.Open();
            string str = "SELECT cast(A_formthreeA.EST_CODE as nvarchar(12)) as EST_CODE, cast(A_formthreeA.EMP_NO as nvarchar(12)) as EMP_NO, A_formthreeA.TOTWAGES, A_formthreeA.PFT, A_formthreeA.TOTEE, A_formthreeA.TOTER, A_formthreeA.EMP_NAME,A_formthreeA.FinYr, company_details.company_name,";
             str += "company_details.comp_address1, company_details.comp_address2,company_details.pf_city_init, company_details.pf_state_init ";
            str += " FROM A_formthreeA INNER JOIN company_details ON A_formthreeA.EST_CODE = company_details.pf_Code ";
            TextObject txtFrom, txtTo;
            SqlCommand cmd = new SqlCommand(str, con);
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable();
            da.Fill(dt);
            rpt.Load(Server.MapPath("..") + "\\Report\\form6A.rpt");
            rpt.SetDatabaseLogon("sa", "Gnk1961", "SUPER/SQLEXPRESS", "Dummy");
            txtFrom = (TextObject)rpt.ReportDefinition.ReportObjects["txtFrom"];
            txtTo = (TextObject)rpt.ReportDefinition.ReportObjects["txtTo"];
            rpt.SetDataSource(dt);
            rpt.SetParameterValue("est_code", drp_compname.SelectedValue.Trim());
            rpt.SetParameterValue("finyr", txt_year.Text);
            txtFrom.Text = txt_year.Text;
            if (txt_year.Text != "")
            {
                txtTo.Text = Convert.ToString(Convert.ToInt16(txt_year.Text) + 1);
            }
        }
        catch(Exception e)
        {
            e.Message.ToString();
        }
        showReport(rpt);
        con.Close();
       
    }