Error 2115 finding record

Hi Experts,

I have 2 listboxes, one giving a subset of the other.   I want to be able to click on the second listbox, and then show that individual record in the fields on my form.

Using:

Dim rs As Object
Set rs = Me.Recordset.Clone
rs.FindFirst "[OrdersDeliveryID] = " & Str(Me![DeliveryListbox])
Me.Bookmark = rs.Bookmark

This works.

However, I'd like to set the first listbox so that if I click a record, it goes to the first record in the second listbox, and displays the data.  

So, this should work:

Private Sub BreakdownListbox_AfterUpdate()
'Me.OrdersBreakdownRef = Me.BreakdownListbox
'Me.OrdersRef = Forms!Orders!OrdersID
Me.DeliveryListbox.Requery
If Me.DeliveryListbox.ListCount = 0 Then
'if empty new record?
Else
With Me.DeliveryListbox
     .Selected(1) = True
     .Value = .ItemData(1)
End With
Dim rs As Object
Set rs = Me.Recordset.Clone
rs.FindFirst "[OrdersDeliveryID] = " & Str(Me![DeliveryListbox])
Me.Bookmark = rs.Bookmark
End If
End Sub

However I get an 2115 error, which I understand means the record is already being updated - I just don't know how to get round it.

Any ideas?