Catastrophic Error with Slicer To Select x Days

I have the following code which works perfect well in one workbook but when I run in another provides me with Run-time error '-2147418113(8000ffff) Automation error Catastrophic Failure.

Does anyone have any idea as to why this happens and further more have a solution to resolve this?

Cheers

Sub RefreshSlicer()
'
'Updates Slicer with last 32 entries
'
     Dim lngIndex As Long
     Dim blnSelected As Boolean
'
     With ThisWorkbook.SlicerCaches("Slicer_FinishedDate")
         blnSelected = True
         For lngIndex = 1 To .SlicerItems.Count
             If lngIndex > 32 Then
                 blnSelected = False
             End If
             .SlicerItems(lngIndex).Selected = blnSelected
         Next
     End With
End Sub

Could anyone suggest an alternative way this might be coded to achieve the same results?

Okay, after much ado I have managed to stop the error by changing "With ThisWorkbook" to "With ActiveWorkbook" - however, I now have another problem in that it appears to be continually calculating the pivot table record and I have to interrupt the code. Once I've interrupted the code, it highlights the line after the "End If" statement. Again, anyone got any suggestions as to what the problem is and what I would have to do to correct it? Thanks