Asp.net Kayıt Hatası

 
  protected void Btkaydol_Click(object sender, EventArgs e) 
      { 
       OleDbConnection con = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0; DATA Source=" + Server.MapPath("kitap.accdb")); 
          con.Open(); 
   
          String sql = "Insert INTO kullanici(adi,soyadi,cinsid,dog_tar,sehirid,telno,eposta,sifre,sifretekrar) Values (@adi,@soyadi,@cinsid,@dog_tar,@sehir_id,@telno,@eposta,@sifre,@sifretekrar)"; 
              OleDbCommand cmd = new OleDbCommand(sql, con); 
          cmd.Parameters.AddWithValue("@adi" ,OleDbType.VarChar).Value = tbadi.Text; 
          cmd.Parameters.AddWithValue("@soyadi" ,OleDbType.VarChar).Value = tbsoyadi.Text;  
    cmd.Parameters.AddWithValue("@cinsid" ,OleDbType.VarChar).Value = ddlcinsiyet.SelectedItem.Text; 
          cmd.Parameters.AddWithValue("@dog_tar" ,OleDbType.VarChar).Value = ddlgun.SelectedItem.Text + "/" + ddlay.SelectedItem.Text+"/" + ddlyil.SelectedItem.Text; 
           cmd.Parameters.AddWithValue("@sehirid" ,OleDbType.VarChar).Value = ddlsehir.SelectedItem.Text; 
          cmd.Parameters.AddWithValue("@telno" ,OleDbType.VarChar).Value = tbtelno.Text; 
          cmd.Parameters.AddWithValue("@eposta" ,OleDbType.VarChar).Value = tbeposta.Text; 
           cmd.Parameters.AddWithValue("@sifre" ,OleDbType.VarChar).Value = tbsifre.Text; 
          cmd.Parameters.AddWithValue("@sifretr" ,OleDbType.VarChar).Value = tbsifretr.Text; 
             [font="Trebuchet MS"][/font] 
          cmd.ExecuteNonQuery(); 
          con.Close(); 
      } 
   
  

 
  cmd.Parameters.AddWithValue("@adi" ,tbadi.Text); 
              cmd.Parameters.AddWithValue("@soyadi", tbsoyadi.Text); 
              cmd.Parameters.AddWithValue("@cinsid",  ddlcinsiyet.SelectedItem.Text); 
              cmd.Parameters.AddWithValue("@dog_tar", ddlgun.SelectedItem.Text + "/" + ddlay.SelectedItem.Text + "/" + ddlyil.SelectedItem.Text); 
              cmd.Parameters.AddWithValue("@sehirid", ddlsehir.SelectedItem.Text); 
              cmd.Parameters.AddWithValue("@telno", tbtelno.Text); 
              cmd.Parameters.AddWithValue("@eposta", tbeposta.Text); 
              cmd.Parameters.AddWithValue("@sifre",  tbsifre.Text); 
              cmd.Parameters.AddWithValue("@sifretr", tbsifretr.Text); 
   
  

protected void Btkaydol_Click(object sender, EventArgs e) 
      { 
       OleDbConnection con = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0; DATA Source=" + Server.MapPath("kitap.accdb")); 
          con.Open(); 
   
          String sql = "Insert INTO kullanici(adi,soyadi,cinsiyet,dog_tar,sehir,telno,eposta,sifre) Values (@adi,@soyadi,@cinsid,@dog_tar,@sehir_id,@telno,@eposta,@sifre)"; 
              OleDbCommand cmd = new OleDbCommand(sql, con); 
              cmd.Parameters.AddWithValue("@adi" ,tbadi.Text); 
              cmd.Parameters.AddWithValue("@soyadi", tbsoyadi.Text); 
              cmd.Parameters.AddWithValue("@cinsiyet",  ddlcinsiyet.SelectedItem.Text); 
              cmd.Parameters.AddWithValue("@dog_tar", ddlgun.SelectedItem.Value + "." + ddlay.SelectedItem.Value + "." + ddlyil.SelectedItem.Value); 
              cmd.Parameters.AddWithValue("@sehir", ddlsehir.SelectedItem.Text); 
              cmd.Parameters.AddWithValue("@telno", tbtelno.Text); 
              cmd.Parameters.AddWithValue("@eposta", tbeposta.Text); 
              cmd.Parameters.AddWithValue("@sifre",  tbsifre.Text); 
          cmd.ExecuteNonQuery(); 
          con.Close(); 
      } 
  }