Add User to Group

[danasegarane]

Hi all ,
I am using this link to add a Domain user to the administrator group of my system. But I am getting the error as "The user name is invalid"

Can any one help

Dana

 

[danasegarane]

Here is my code

Imports System.DirectoryServices
 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        AddUsertoComputer("\\mydomain\dana", "ftest", True, "Danasekarane")
    End Sub
    Public Shared Function AddUsertoComputer(ByVal nusername As String, ByVal npwd As String, ByVal isadmin As Boolean, ByVal ndisplayname As String) As String
        Try

            Dim AD As DirectoryEntry = New DirectoryEntry("WinNT://" + SystemInformation.ComputerName + ",computer")
            Dim entry As DirectoryEntries = AD.Children
            Dim nuser As DirectoryEntry = entry.Add(nusername, "User")
            nuser.Properties("FullName").Add("ndisplayname")
            nuser.Invoke("Setpassword", npwd)
            nuser.CommitChanges()
            Dim grp As DirectoryEntry
            If isadmin Then
                grp = AD.Children.Find("Administrator", "group")
                If Not grp Is Nothing Then
                    grp.Invoke("Add", New Object, nuser.Path.ToString)
                End If
            End If
            Return ""
        Catch ex As Exception
            Return ex.Message.ToString
        End Try
    End Function