vb.net and compact framework?

[tableray]

im just trying out to program a pda application

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        MsgBox("it works")
    End Sub
End Class

however i keep getting the following error:

The version of the assembly System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089 cannot be loaded by this version of the Microsoft .NET Compact Framework.

A first chance exception of type 'System.MissingMethodException' occurred in SmartDeviceProject1.exe

it only happens when i deploy it to my device.. works fine when i use the emulator.. can somebody explain?