Invalid Procedure Call or Argument

I have just copied an EXCEL spreadsheet M/S 2007 - from a W7 to a W8 environment and get the error "Invalid Procedure Call or Argument"
The code that seems to be failing is

On Error GoTo err
With ActiveSheet
.ExportAsFixedFormat _
Type:=xlTypePDF, _
Filename:=FileFullPath, _
Quality:=xlQualityStandard, _
IncludeDocProperties:=True, _
IgnorePrintAreas:=False, _
OpenAfterPublish:=True


The code immediately preceeding this is

Sub Send_Acative_Spreadsheet_as_PDF_via_Gmail()

' PART1 - Create a PDF file of the active worksheet

Dim OlApp As Object
Dim NewMail As Object
Dim TempFilePath As String
Dim TempFileName As String
Dim FileFullPath As String

With Application
.ScreenUpdating = False
.EnableEvents = False
End With

' Temporary file path where pdf
' file will be saved before
' sending it in email by attaching it.

'TempFilePath = Environ$("C:\Invoices") & "\"
TempFilePath = Environ$("temp") & "\"
' Now append a date and time stamp
' in your pdf file name. Naming convention
' can be changed based on your requirement.

TempFileName = ActiveSheet.Name & "-" & Format(Now, "dd-mmm-yy h-mm-ss") & ".pdf" '

'TempFileName = ActiveSheet.Name & "-" & Format(Now, "dd-mmm-yy h-mm-ss") & ".pdf"
'TempFileName = ActiveSheet.Name & ".pdf"
'Complete path of the file where it is saved
FileFullPath = TempFilePath & TempFileName

'Now Export the Activesshet as PDF with the given File Name and path



Any ideas please

Please use CODE tags when posting code, it makes it much better to read and possibly identify the problem(s)

Sorry this is my first port - how do i use a CODE tag please.