Working For months, now broken

[JPARKHURST]

Did I miss an update, something with excel or ...?

This code is (all stored in a module, save for the workbook_open):

Public Function CnSwS(wb101 As Workbook, ws101 As Worksheet, sws101 As String)  'Check to see if Worksheet variables have been established, and if not, establish them!
    If ws101 Is Nothing Then
        Set ws101 = wb101.Sheets(sws101) 'this is the line erring
    End If
End Function

has been working for months, and is now not working. "Run-time error 9" Subscript out of range

It is called here:

Public Sub FireOpen()
    'Check & See if things need to be reset
    'Set wbThis = CnSwB(wbThis)
    Call CnSwB(wbThis)
    Call CnSwS(wbThis, wsDashboard, "Dashboard")
    Call CnSwS(wbThis, wsWorkingDispatch, "Working_Dispatch")
    Call CnSwS(wbThis, wsJobDispatch, "Job_Dispatch")
    Call CnSwS(wbThis, wsShortages, "Shortages")
    Call CnSwS(wbThis, wsShippingRequirements, "Shipping_Requirements")
    Call CnSwS(wbThis, wsResprayReport, "Respray_Report")
End Sub

and it is called on doc open.

Public Sub Workbook_Open()
 Call FireOpen
End Sub

Here is the workbook variable set

Public Function CnSwB(wb100 As Workbook)
  'Check to see if Workbook is established, if not, establish it!
    If wb100 Is Nothing Then
        Set wb100 = ThisWorkbook
    End If
    'CnSwB = wb100
End Function

I am at a loss. Any help or direction would be appreciated.

 

[JPARKHURST]

Greyed out, so i would guess not?