What file do I need to register?

I am creating an application that will read the emails from Outlook's Inbox. I have this part working. Now I am trying to read the SMTP From address a selected email. I know this works differently with the Outlook versions before 2003. I have checked out CDOLive and am using scripts from there to get the SMTP address.

I am creating a VS2005 Windows app. I have as added references Outlook 11.0 object. The project is a test project so it just lists the emails in a grid, then I try to get the SMTP email address.

The project works fine in developement with Outlook 2003 and 2007 but when I try it on Outlook 2000 I get a "Cannot create ActiveX component" error.

I cannot debug it through Outlook 2000 so I can't see what is going on. I have one customer who is getting the "Cannot create ActiveX component" error with Outlook 2003.
The error is occurring at: objSession = CreateObject("MAPI.Session")

I have googled this to death and the main thing that comes through is that a file may need to be reregistered. I have checked on the maching that I am installing the test project on and they are in the registry. The only referenced dependicies that are included with the install project are office.dll, and the outlook interop. Does this mean I need to re-register one of these?
Any ideas would be appreciated.

On to the code:

vb Code:

Function GetFromAddress(ByVal EntryID As String, ByVal ParentStoreID As String, ByRef ReturnFromAddresses As String, Optional ByVal Outlook2000 As Boolean = False) As Boolean ', ByRef ReturnFromAddresses As String) As Boolean
        Dim ReturnBool As Boolean = True
       
 
        'Get the SMTP address of the originator of a message
        ' You can read the SMTP address of the originator of a message. But if you try to use objAddressEntry.Address you will receive the Exchange address (also known as 'Distinguish Name' if the originator is an Exchange mailbox) and not the SMTP address. Here is how to read the SMTP address:
        ' MAPI property tag for SMTP address
        Dim objSession As New Object, objFolder As New Object, objMessages As New Object, objMessage As New Object
        Dim objField As New Object, objCDOMessage As New Object, objAddEntry As New Object
        Const CdoPR_EMAIL As Integer = &H39FE001E
        Const PR_EMS_AB_PROXY_ADDRESSES As Integer = &H800F101E
        Try
 
            Dim strAddressEntryID As String = ""
 
            'set the ReturnFromAddresses to blank
            ReturnFromAddresses = ""
 
            strErrorString = "Start MAPI Session"
            objSession = CreateObject("MAPI.Session")
 
            strErrorString = "MAPI Session Logon"
            objSession.Logon("", "", False, False, 0)
 
            If Outlook2000 Then
                'using outlook 2000
                ' Get first message from inbox
                strErrorString = "2000: Get Inbox"
                objFolder = objSession.Inbox
 
                strErrorString = "2000: Get Folder Messages"
                objMessages = objFolder.Messages
 
                strErrorString = "2000: Get Message(EntryID,StoreID)"
                objMessage = objMessages.GetMessage(EntryID, ParentStoreID)
 
                ' Get address
                strErrorString = "2000: Get Address Entry"
                objAddEntry = objMessage.Sender
 
                strErrorString = "2000: Get Address From AddEntry"
                ReturnFromAddresses = objAddEntry.Address
 
                ' Check if it is an Exchange object
                strErrorString = "2000: Check for /O="
                If Microsoft.VisualBasic.Left(ReturnFromAddresses, 3).ToUpper = "/O=" Then
 
                    ' Get the SMTP address
                    strErrorString = "2000: Get CdoPR_Email"
                    strAddressEntryID = objAddEntry.ID
                    ReturnFromAddresses = objSession.GetAddressEntry(strAddressEntryID).Fields(CdoPR_EMAIL).Value()
 
                End If
 
 
            Else
                'using outlook 2002 +
                strErrorString = "2002+: Get CDO Message"
                objCDOMessage = objSession.GetMessage(EntryID, ParentStoreID)
 
                strErrorString = "2002+: Get CDO Sender"
                objAddEntry = objCDOMessage.Sender
 
                strErrorString = "2002+: Get PR_EMS_AB_PROXY_ADDRESSES"
                objField = objAddEntry.Fields(PR_EMS_AB_PROXY_ADDRESSES)
 
                strErrorString = "2002+: Loop Through Addresses"
                For Each strEMailAddress As String In objField.Value
                    If Microsoft.VisualBasic.Left(strEMailAddress, 5) = "SMTP:" Then
                        ReturnFromAddresses = Microsoft.VisualBasic.Mid(strEMailAddress, 6)
                        Exit For
                    End If
                Next
 
            End If
 
            ' Display the SMTP address of current user
            MessageBox.Show("SMTP address of current user: " & ReturnFromAddresses, UtilityName, MessageBoxButtons.OK, MessageBoxIcon.Information)
 
            'Note that you must use exactly the way described above. Otherwise you will fail to get the SMTP address.
 
        Catch exp As System.UnauthorizedAccessException
            MessageBox.Show("If you say NO to the security boxes then email will NOT be gathered", "Email Inbox", _
               MessageBoxButtons.OK, MessageBoxIcon.Information)
            ReturnBool = False
            Exit Try
 
        Catch exp As System.Exception
            MessageBox.Show("GetAddress error: " & strErrorstring & vbCrLf & exp.Message, UtilityName, MessageBoxButtons.OK)
 
            ReturnBool = False
        End Try
 
        'cleanup
        objSession = Nothing : objFolder = Nothing : objMessages = Nothing : objMessage = Nothing : objField = Nothing : objCDOMessage = Nothing : objAddEntry = Nothing
        ReturnBool = Not IsNullOrEmpty(ReturnFromAddresses)
End Function