ASP.NET

Hi, I was creating a login form in visual web developer express. In my web.config, I have inserted these codes for the connection of my database:

<connectionStrings>
    <clear />
    <add name="LocalSQLServer"
      connectionString="Server=.;Database=youtubelogin;Trusted_Connection=Yes;" />
  </connectionStrings>

The problem is when I add a Login control on my page, and click on the ASP.Net configuration website for the security to add roles, I got this error:

The connection name 'ApplicationServices' was not found in the applications configuration or the connection string is empty. (c:\documents and settings\ali\my documents\visual studio 2010\Projects\Youtube\Youtube\web.config line 25)

Here is my entire web.config below:

<?xml version="1.0"?>

<configuration>
  <connectionStrings>
    <clear />
    <add name="LocalSQLServer"
      connectionString="Server=.;Database=youtubelogin;Trusted_Connection=Yes;" />
  </connectionStrings>

  <system.web>
    <compilation debug="true" strict="false" explicit="true" targetFramework="4.0" />

    <authentication mode="Forms">
      <forms loginUrl="~/Account/Login.aspx" timeout="2880" />
    </authentication>

    <membership>
      <providers>
        <clear/>
        <add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="ApplicationServices"
             enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false"
             maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10"
             applicationName="/" />
      </providers>
    </membership>

    <profile>
      <providers>
        <clear/>
        <add name="AspNetSqlProfileProvider" type="System.Web.Profile.SqlProfileProvider" connectionStringName="ApplicationServices" applicationName="/"/>
      </providers>
    </profile>

    <roleManager enabled="false">
      <providers>
        <clear/>
        <add name="AspNetSqlRoleProvider" type="System.Web.Security.SqlRoleProvider" connectionStringName="ApplicationServices" applicationName="/" />
        <add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/" />
      </providers>
    </roleManager>

  </system.web>

  <system.webServer>
     <modules runAllManagedModulesForAllRequests="true"/>
  </system.webServer>
</configuration>

Help me, I'm a beginner..

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class Admin_NhanVien_Admin : System.Web.UI.Page
{
    CTH51Cls.NhanVien nv = new CTH51Cls.NhanVien();
    CTH51Cls.PhongBan ph = new CTH51Cls.PhongBan();

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            griNhanVien.DataSource = nv.DS();
            griNhanVien.DataBind();
            droPhongBan.DataSource = ph.DS();
            droPhongBan.DataBind();
        }
    }

    protected void btnThem_Click(object sender, EventArgs e)
    {
        CTH51Cls.NhanVien nv = new CTH51Cls.NhanVien();
        txtHoTen.Text = txtHoTen.Text.Trim();
        while (txtHoTen.Text.IndexOf("  ") >= 0)
        {
            txtHoTen.Text = txtHoTen.Text.Replace("  ", " ");
        }
        nv.HoNV = txtHoTen.Text.Substring(0, txtHoTen.Text.LastIndexOf(" "));
        nv.TenNV = txtHoTen.Text.Substring(txtHoTen.Text.LastIndexOf(" ") + 1);
        nv.DienThoai = txtDienThoai.Text;
        nv.GioiTinh = chkGioiTinh.Checked;
        nv.DiaChi = txtDiaChi.Text;
        if (fileAnhNV.HasFile)
            if (System.IO.File.Exists(Server.MapPath("~/Resource/Staff/") + fileAnhNV.FileName))
                nv.AnhNV = "";
            else
            {
                nv.AnhNV = fileAnhNV.FileName;
                string duongdan = Server.MapPath("~/Resource/Staff/");
                fileAnhNV.SaveAs(duongdan + fileAnhNV.FileName);
            }
        else
            nv.AnhNV = "";
        nv.Email = txtEmail.Text;
        nv.MatKhau = txtEmail.Text;
        nv.MaPB = int.Parse(droPhongBan.SelectedValue);
        nv.Them();
        griNhanVien.DataSource = nv.DS();
        griNhanVien.DataBind();
        txtMaNV.Text = "";
        txtHoTen.Text = "";
        txtDienThoai.Text = "";
        txtDiaChi.Text = "";
        txtEmail.Text = "";
        imgAnhNV.ImageUrl = "";
        chkGioiTinh.Checked = false;
    }


    protected void griNhanVien_SelectedIndexChanged(object sender, EventArgs e)
    {
        nv.MaNV = int.Parse(griNhanVien.SelectedValue.ToString());
        nv.CT();
        txtMaNV.Text = nv.MaNV.ToString();
        txtHoTen.Text = nv.HoNV + " " + nv.TenNV;
        txtDienThoai.Text = nv.DienThoai;
        chkGioiTinh.Checked = nv.GioiTinh;
        txtDiaChi.Text = nv.DiaChi;
        if (nv.AnhNV != "")
            imgAnhNV.ImageUrl = "~/Resource/Staff/" + nv.AnhNV;
        else imgAnhNV.ImageUrl = "";
        txtEmail.Text = nv.Email;
        droPhongBan.SelectedValue = nv.MaPB.ToString();
        imgAnhNV.ToolTip = imgAnhNV.ImageUrl.Substring(imgAnhNV.ImageUrl.LastIndexOf("/") + 1);
    }


    protected void btnXoa_Click(object sender, EventArgs e)
    {
        CTH51Cls.NhanVien nv = new CTH51Cls.NhanVien();
        nv.MaNV = int.Parse(txtMaNV.Text);
        nv.Xoa();
        griNhanVien.DataSource = nv.DS();
        griNhanVien.DataBind();
        if (System.IO.File.Exists(Server.MapPath(imgAnhNV.ImageUrl)))
        System.IO.File.Delete(Server.MapPath(imgAnhNV.ImageUrl));
        txtMaNV.Text = "";
        txtHoTen.Text = "";
        txtDienThoai.Text = "";
        txtDiaChi.Text = "";
        txtEmail.Text = "";
        chkGioiTinh.Checked = false;
    }


    protected void btnSua_Click(object sender, EventArgs e)
    {
        CTH51Cls.NhanVien nv = new CTH51Cls.NhanVien();
        nv.MaNV = int.Parse(txtMaNV.Text);
        nv.HoNV = txtHoTen.Text.Substring(0, txtHoTen.Text.LastIndexOf(" "));
        nv.TenNV = txtHoTen.Text.Substring(txtHoTen.Text.LastIndexOf(" ") + 1);
        nv.DienThoai = txtDienThoai.Text;
        nv.GioiTinh = chkGioiTinh.Checked;
        nv.DiaChi = txtDiaChi.Text;
        if (fileAnhNV.HasFile)
        {
            if (System.IO.File.Exists(Server.MapPath(imgAnhNV.ImageUrl)))
            System.IO.File.Delete(Server.MapPath(imgAnhNV.ImageUrl));
            if (System.IO.File.Exists(Server.MapPath("~/Resource/Staff/") + fileAnhNV.FileName))
                nv.AnhNV = "";
            else
            {
                nv.AnhNV = fileAnhNV.FileName;
                string duongdan = Server.MapPath("~/Resource/Staff/");
                fileAnhNV.SaveAs(duongdan + fileAnhNV.FileName);
            }
        }
        else
            nv.AnhNV = imgAnhNV.ImageUrl.Substring(imgAnhNV.ImageUrl.LastIndexOf("/") + 1);
        nv.Email = txtEmail.Text;
        nv.MatKhau = txtEmail.Text;
        nv.MaPB = int.Parse(droPhongBan.SelectedValue);
        nv.Sua();
        griNhanVien.DataSource = nv.DS();
        griNhanVien.DataBind();
        txtMaNV.Text = "";
        txtHoTen.Text = "";
        txtDienThoai.Text = "";
        txtDiaChi.Text = "";
        txtEmail.Text = "";
        imgAnhNV.ImageUrl = "";
        chkGioiTinh.Checked = false;
    }
}