Get AD attribute using .net 1.1

This below code works perfectly in vb 2005 but can't work in .net 1.1.

Private Function GetActiveDirUserDetails(ByVal useame As String) As String
        Dim dirEntry As System.DirectoryServices.DirectoryEntry
        Dim dirSearcher As System.DirectoryServices.DirectorySearcher
        Try
            dirEntry = New System.DirectoryServices.DirectoryEntry("LDAP://123.45.67.89:101/DC=mydomain,DC=com")
            dirSearcher = New System.DirectoryServices.DirectorySearcher(dirEntry)
            dirSearcher.Filter = "(samAccountName=" & useame & ")"
            Dim sr As DirectoryServices.SearchResult = dirSearcher.FindOne()
            If sr Is Nothing Then
                Retu False
            End If

            Dim de As System.DirectoryServices.DirectoryEntry = sr.GetDirectoryEntry()
            'Dim firstname = de.Properties("GivenName").Value.ToString()
            'Dim lastname = de.Properties("sn").Value.ToString()
            'Dim fullname = de.Properties("DisplayName").Value.ToString()

            Dim ObjFirstName As String = ""
            Dim ObjLastName As String = String.Empty
            Dim ObjEmail As String = ""

            Try
                ObjEmail = de.Properties("mail").Value.ToString()
                ObjFirstName = de.Properties("GivenName").Value.ToString()
                ObjLastName = de.Properties("sn").Value.ToString()

            Catch ex As Exception
                ObjFirstName = de.Properties("DisplayName").Value.ToString()
            End Try

            MsgBox(ObjFirstName + ObjLastName + ObjEmail)
            Retu ObjFirstName
            Retu ObjLastName
            Retu ObjEmail

        Catch ex As Exception ' retu false if exception occurs 
            Retu ex.Message
            MsgBox(ex.Message)
        End Try
    End Function

When I press the button, it shows nothing. I am trying to get AD attributes here. Anybody can help?