using crystal report??

i have this code

try
            {
                cls_Koneksi_DB.objConn.Open();
                F_Laporan_Pembelian_Barang lapBeli = new F_Laporan_Pembelian_Barang();
                CR_Pembelian_Barang laporan = new CR_Pembelian_Barang();
                if (this.radioButton1.Checked == true)
                {
                    laporan.RecordSelectionFormula = "";
                }               
                if (this.radioButton2.Checked == true)
                {
                    laporan.RecordSelectionFormula = "{t_Data_Barang.Tanggal}>='" + dateTimePicker1.Text + "'AND{t_Data_Barang.Tanggal}<='" + dateTimePicker2.Text + "'";

                }
               
                lapBeli.CR_Beli.DisplayGroupTree = true;// on this row  "Error    1    'SID_TBJATIMULYA.F_Laporan_Pembelian_Barang.CR_Beli' is inaccessible due to its protection level"

                lapBeli.CR_Beli.ReportSource = laporan;
                lapBeli.CR_Beli.Refresh();
                lapBeli.Show();
            }
            catch (SqlException en)
            {
                MessageBox.Show("adfasd," + en.ToString() + "");
            }
            finally
            {
                cls_Koneksi_DB.objConn.Close();
            }


can give me for solution??