Exposing .NET components to COM [2005]

Hello,

I'm attempting to call a .NET class module from a COM enabled non .NET environment (microsoft excel) using a COM callable wrapper. I'm quite new to all of this and unfortunately still can't get it to work. I've included the code below - can anyone help me to get this to work?

many thanks

Code:

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Imports System
Imports System.Runtime.InteropServices

Namespace Strength

    <InterfaceType(ComInterfaceType.InterfaceIsIDispatch)> Public Interface Interp
        Function Interpolate(ByVal ply_thickness As Double, _
        ByVal fastener_diameter As String, ByVal fastener_code As String, ByVal joint_matl As String) As String
    End Interface

    <ClassInterface(ClassInterfaceType.None)> Public Class Strength
        Implements Interp

        Public Strength()

        Dim doc As New System.Xml.XmlDocument()
        Dim trans As New System.Xml.Xsl.XslCompiledTransform()
        Dim mem As New System.IO.MemoryStream()
        Dim args As New System.Xml.Xsl.XsltArgumentList

        Public Function Interpolate(ByVal ply_thickness As Double, ByVal fastener_diameter As String, _
        ByVal fastener_code As String, ByVal joint_matl As String) As String Implements Interp.Interpolate

.............

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