excel - Select Case での実行時エラー 9

Question

以下のスクリプトが機能する場合もありますが、通常はタイトルにエラー メッセージが表示されます。オブジェクトと変数に監視を設定しましたが、エラーが発生したときにすべてが定義されているか、適切な値を持っているように見えるため、困惑しています。助言がありますか？

Public Sub PopulateDepositDetails()

    Set BT = Workbooks("US98 1650 Backup Template.xlsx")

    Set DD = BT.Sheets("Deposit Details")
    Set RDI = BT.Sheets("Raw Database Info")
    LastRowRDI = RDI.Cells(Rows.Count, 1).End(xlUp).Row

    'Define Trading Partner(Company Number) Range
    Dim x, ColX As Range, nrDD, rownum As Integer
    Set ColX = RDI.Range(Cells(4, 24).Address, Cells(LastRowRDI, 24).Address)

    nrDD = 2    ' sets Deposit Details sheet next row

    Dim COName As String

    COName = InputBox(Prompt:="Enter Company to Process", _
                      Title:="ENTER COMPANY")

    If COName = vbNullString Then
        Exit Sub

    Else

        Select Case COName

            Case "US96"

                For Each x In ColX
                    If x = "US96" And x.Offset(0, 4) = "YES" Then
                        nrDD = nrDD + 1
                        x.EntireRow.Copy Destination:=Sheets("Deposit Details").Range("A" & nrDD)
                    End If
                Next

            Case "US97"
                For Each x In ColX
                    If x = "US97" And x.Offset(0, 4) = "YES" Then
                        nrDD = nrDD + 1
                        x.EntireRow.Copy Destination:=Sheets("Deposit Details").Range("A" & nrDD)
                    End If
                Next

            Case "US98"
                For Each x In ColX
                    If x = "US98" And x.Offset(0, 4) = "YES" Then
                        nrDD = nrDD + 1
                        x.EntireRow.Copy Destination:=Sheets("Deposit Details").Range("A" & nrDD)
                    End If
                Next

            Case "US99"
                For Each x In ColX
                    If x = "US99" And x.Offset(0, 4) = "YES" Then
                        nrDD = nrDD + 1
                        x.EntireRow.Copy Destination:=Sheets("Deposit Details").Range("A" & nrDD)
                    End If
                Next

            Case "USZ0"
                For Each x In ColX
                    If x = "USZ0" And x.Offset(0, 4) = "YES" Then
                        nrDD = nrDD + 1
                        x.EntireRow.Copy Destination:=Sheets("Deposit Details").Range("A" & nrDD)
                    End If
                Next

        End Select

    End If

End Sub