VB.NET Shutdown fails to execute in WindowsXP

[smilbuta]

Hello, I have reviewd many of the threads here on how to shutdown a system and created this code using the VB.NET cookbooks solution.

Public Class Form1
    Inherits System.Windows.Forms.Form
 
    Private Declare Function ExitWindowsEx Lib "user32" (ByVal uFlags As Long, ByVal dwReserved As Long) As Long
 
 
    Private Enum windowsexitflags
        logoff = 0
        Shutdown = 1
    End Enum
    Private Sub btnShutdown_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnShutdown.Click
        MessageBox.Show("Test before")'to see if im going through the button press
        ExitWindowsEx(windowsexitflags.Shutdown, 1&)
        MessageBox.Show(" Test after")
    End Sub
    Private Sub btnNo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnNo.Click
        ExitWindowsEx(windowsexitflags.logoff, 0&)
    End Sub
    Private Sub btnYes_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnYes.Click
        Me.Close()
    End Sub
End Class

MY Problem is LOGOFF works, SHUTDOWN does not... I do not understand why. Console app is being run on a windows XP SP2 box under administrative privilges. Any sugestions would be appreciated.