Serialization Problem

I keep getting the following error:

An unhandled exception of type 'System.InvalidOperationException' occurred in system.xml.dll

Additional information: There was an error reflecting type 'RaptorMain.CurrentState'.


This is how i'm attempting to serialize:

Code:

---

        cs = New CurrentState
        fillCurrentState() 'fills the class properties

        If IO.File.Exists("data.xml") Then IO.File.Delete("data.xml")
        'make the file and stream
        Dim fs As New IO.FileStream("data.xml", IO.FileMode.CreateNew)
        'serialize it to xml data
        Dim xf As New Xml.Serialization.XmlSerializer(GetType(CurrentState))
        xf.Serialize(fs, cs)
        fs.Close()

---

And the class i'm attempting to serialize:

Code:

---

<Serializable()> Public Class CurrentState

#Region "Member Variables"
    Private Side1ConcentrationValue As Double
        .
        .
        .
    Private tons_RB_CheckedValue As Boolean = False
#End Region
#Region "Member Properties"
    Public Property tons_RB_Checked() As Boolean
        Get
            Return tons_RB_CheckedValue
        End Get

        Set(ByVal Value As Boolean)
            tons_RB_CheckedValue = Value
        End Set
        .
        .
        .
    End Property
#End Region

    Public Sub New()

    End Sub
End Class

---

:confused: Any Ideas?