Method 'Range' of objects'_worksheet' failed

Hi All

Was wondering if anyone knows why I would be getting this error (Method 'Range' of objects'_worksheet' failed) when I try and run this code?
The code works fine on the first sheet (Sheet1) but not on any of the remaining sheets (Sheet7 - Sheet 13)

Dim ws As Worksheet
Dim del2 As Long
del2 = TextBox5.Value

For Each ws In ActiveWorkbook.Worksheets
If ws.CodeName = "Sheet1" Or ws.CodeName = "Sheet7" Or ws.CodeName = "Sheet8" Or ws.CodeName = "Sheet9" Or ws.CodeName = "Sheet10" Or ws.CodeName = "Sheet11" Or ws.CodeName = "Sheet12" Or ws.CodeName = "Sheet13" Then

Select Case del2
Case 1 To 13
x = 16 - (13 - del2)

'Commision Charge Static Test
ws.Range(Cells(21, x), Cells(23, 15)).ClearContents                'Clear contents of unused cells first row of commision charge static test
ws.Range("B24", "O41").Clear                                       'Clear unused rows from commision charge static test
ws.Range("B23", "O23").Borders(xlEdgeBottom).LineStyle = xlDouble  'Adds boarder back to bottom of row 23

'Capacity Static Test
ws.Range(Cells(174, x), Cells(176, 15)).ClearContents                'Clear contents of unused cells first row of capacity static test
ws.Range("B177", "O194").Clear                                       'Clear unused rows from capacity static test
ws.Range("B176", "O176").Borders(xlEdgeBottom).LineStyle = xlDouble  'Adds boarder back to bottom of row 176

'Pre Recharge Static Test
ws.Range(Cells(338, x), Cells(340, 15)).ClearContents                'Clear contents of unused cells first row of pre recharge static test
ws.Range("B341", "O358").Clear                                       'Clear unused rows from pre recharge static test
ws.Range("B340", "O340").Borders(xlEdgeBottom).LineStyle = xlDouble  'Adds boarder back to bottom of row 340

'Pre HDC Static Test
ws.Range(Cells(499, x), Cells(501, 15)).ClearContents                'Clear contents of unused cells first row of pre HDC static test
ws.Range("B502", "O519").Clear                                       'Clear unused rows from pre HDC static test
ws.Range("B501", "O501").Borders(xlEdgeBottom).LineStyle = xlDouble  'Adds boarder back to bottom of row 501

'After HDC Test
ws.Range(Cells(548, x), Cells(550, 15)).ClearContents                'Clear contents of unused cells first row of after HDC static test
ws.Range("B551", "O568").Clear                                       'Clear unused rows from after HDC static test
ws.Range("B550", "O550").Borders(xlEdgeBottom).LineStyle = xlDouble  'Adds boarder back to bottom of row 550

'Final Static Test
ws.Range(Cells(597, x), Cells(599, 15)).ClearContents                'Clear contents of unused cells first row of final static test
ws.Range("B600", "O617").Clear                                       'Clear unused rows from Final Static Test
ws.Range("B599", "O599").Borders(xlEdgeBottom).LineStyle = xlDouble  'Adds boarder back to bottom of row 599


End Select
End If
Next ws