Compile Error with VBA to move conversation to PST file

I'm trying to write some VBA to move the conversation I have selected in Outlook to a PST file named PSTFileName. I have the code below based on some other research but I keep getting a "Compile Error Method or data member not found" and it is erroring on the OlSelectionContents item.
Any help at all would be greatly appreciated.

Code:

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Sub MoveSelectedConversationToPSTFolder(PSTFileName As String)
    Set Conversations = ActiveExplorer.Selection.GetSelection(Outlook.OlSelectionContents.olConversationHeaders)
    For Each Header In Conversations
        Set Items = Header.GetItems()
        For I = 1 To Items.Count
            Items(I).UnRead = False
            Items(I).Move PSTFileName
        Next I
    Next Header
End Sub

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i think conversation objects are only valid in later versions of outlook

Is there a way to get the information another way? In my inbox I have my messages sorted by conversation so if I have the conversation selected is there another way in Outlook 2007 vba to select all the messages with the same subject (i.e. conversation) and move them?

if only the conversation is selected, you can move all the selected items
otherwise you should be able to use the conversationtopic of each message

Code:

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Set sel = ActiveExplorer.Selection
For Each msg In sel
    Debug.Print msg.ConversationTopic
    msg.Move 'folder to move to
Next

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