Ошибка в VBA Run-time error '9' Subscrpt out of range

For a = 4 To 1200 '37170
    If x Like "*" & Cells(a, 3).Text & "*" Then
        'MsgBox "!"
        i = 3
        c = 7
        Do
            Cells(a + c, 5).Value = Workbooks(x).Sheets(x).Cells(i, 1) ' Ошибка Run-time error '9' Subscrpt out of range
            Cells(a + c, 6).Value = Workbooks(x).Sheets(x).Cells(i, 2)
            b = 3
            For j = 7 To 27
                If j Mod 2 <> 0 Then
                    Cells(a + c, j).Value = Workbooks(x).Sheets(x).Cells(i, b)
                    b = b + 1
                End If
            Next
            i = i + 1
            c = c + 1
        Loop Until Workbooks(x).Sheets(x).Cells(i, 1).Text = ""
    Exit For
    End If
Next

Sub AddZNZ()
 
Dim Filter As String, Title As String, Copyto As String
Dim FilterIndex As Integer
Dim Filename As Variant
Dim y As Integer
Dim i, j, b, c, d As Integer
Dim a As Long
Dim x As String
 
' File filters
Filter = "Excel Files (*.xls),*.xls," & _
          "All Files (*.*),*.*"
FilterIndex = 1
Title = "Оберіть файли для додавання"
Filename = Application.GetOpenFilename(Filter, FilterIndex, Title, , True)
 
On Error Resume Next
' Exit on Cancel
 If Filename <> False Then
 Else
  MsgBox "Файли не були обрані!"
  Exit Sub
  End If
On Error GoTo 0
 
For y = 1 To UBound(Filename)
'Open File
Workbooks.Open Filename(y)
x = ActiveWorkbook.Name
 
'копирование информации в цикле
'лист Загальні відомості
Windows("Luganska_obl_rezultati_ZNO.xls").Activate
Sheets("Відомості по територіям").Select
For a = 4 To 1200 '37170
    If x Like "*" & Cells(a, 3).Text & "*" Then
        'MsgBox "!"
        i = 3
        c = 7
        Do
            Cells(a + c, 5).Value = Workbooks(x).Sheets(x).Cells(i, 1)
            Cells(a + c, 6).Value = Workbooks(x).Sheets(x).Cells(i, 2)
            b = 3
            For j = 7 To 27
                If j Mod 2 <> 0 Then
                    Cells(a + c, j).Value = Workbooks(x).Sheets(x).Cells(i, b)
                    b = b + 1
                End If
            Next
            i = i + 1
            c = c + 1
        Loop Until Workbooks(x).Sheets(x).Cells(i, 1).Text = ""
    Exit For
    End If
Next
 
'close book
   Application.DisplayAlerts = False
 Workbooks.Item(Workbooks.Count).Close (False)
 
   Application.DisplayAlerts = True
    Windows("Luganska_obl_rezultati_ZNO.xls").Activate
    Next
 
End
End Sub

Windows("Luganska_obl_rezultati_ZNO.xls").Activate
Sheets("Відомості по територіям").Select
 
 
 
 
 
i = 11
Do
Cells(i, 1).Value = Workbooks(x).Sheets(x).Cells(i - 8, 1)
Cells(i, 2).Value = Workbooks(x).Sheets(x).Cells(i - 8, 2)
a = 3
For j = 3 To 23
If j Mod 2 <> 0 Then
Cells(i, j).Value = Workbooks(x).Sheets(x).Cells(i - 8, a)
a = a + 1
End If
Next
i = i + 1
Loop Until Workbooks(x).Sheets(x).Cells(i - 8, 1).Text = ""

Workbooks(x).Sheets(x)

Left(x,len(x)-4)