Access 07 - Subforms static number of records selected with DAO.recordset - Error cycling back to first subform

Hello Experts....

I have a form that has 4 subforms.  The subforms use Parent/Child link to bring the correct number of records up.  That part works fine.

On each subform I have an unbound textbox called [txtWaitEnd] that when the that textbox has the focus I execute the following (ALL THE SUBFORMS HAVE THIS SAME UNBOUND TEXTBOX and VBCode):

Private Sub txtWaitEnd_GotFocus()
Dim strSQL As String
Dim rs As DAO.Recordset
Dim a As Long, b As Long, c As Long

a = Me.LVLInfoID

strSQL = "SELECT LVLInfoDtailID, LVLInfoID, LVLMachPollPositionID From tbl_LVLInfoDetails WHERE LVLInfoID=" & a
Set rs = CurrentDb.OpenRecordset(strSQL, dbOpenDynaset)
        If rs.RecordCount > 0 Then
            rs.MoveLast
            rs.MoveFirst
            b = rs.RecordCount
            With rs
                .FindFirst "[LVLMachPollPositionID] = " & Me.LVLMachPollPositionID
                If .AbsolutePosition = b - 1 Then
                    Parent.[sfrm_LVLInfoDetails_AmtOut].SetFocus
                Else
                End If
            End With
        End If

rs.Close
Set rs = Nothing

End Sub

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This works right to cycle thru all of the records on each subform and if it's the last record for that subform then it goes to the next subform etc....

However, the problem is when I get to the last record of the 4th subform.  When the txtWaitEnd gets the focus I get the error:
I don't understand why I'd get this since in each subform I'm "closing" and setting each DAO.recordset to Nothing at the end of every vb instruction.