send sms (could not load sms.dll) HELP!

I have created a device application in VS 2005
I have put the following lines of code in me form
I'm using windows mobile and VB.net. I 'm trying to built an application which will send sms.
Imports Microsoft.WindowsMobile.PocketOutlook
Imports Microsoft.WindowsMobile.PocketOutlook.MessageInterception
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim VBMobileSMS As New SmsMessage("09*********", "this is a test")
VBMobileSMS.Send()
End Sub
End Class

But I am always getting an exception . When I run it in the device I got this
Could not load 'sms.dll'

what could be the possible problem in here ?