Public member 'xlPivotTableSourceType' on type 'ApplicationClass' not found

Dim excel As Microsoft.Office.Interop.Excel.Application
            Dim wb As Microsoft.Office.Interop.Excel.Workbook
            Dim ws As Microsoft.Office.Interop.Excel.Worksheet
            Dim rng As Microsoft.Office.Interop.Excel.Range
 
            excel = New Microsoft.Office.Interop.Excel.Application
            wb = excel.Workbooks.Open(FileToLoad)
            ws = wb.Sheets("Sheet1")
            excel.Visible = True
            wb.Activate()
            
 
Try
 
                Dim xlRange As Excel.Range = DirectCast(ws, Excel.Worksheet).Range("1:65536")
 
                'Create the Pivotcache.
                Dim ptCache As Excel.PivotCache = wb.PivotCaches.Add(SourceType:=excel.XlPivotTableSourceType.xlExternal)
 
                'Create the Pivottable.
                Dim ptTable As Excel.PivotTable = ws.PivotTables.Add(PivotCache:=ptCache, _
                        TableDestination:=xlRange, TableName:="PT_Report")
 
 
 
                'Setup the Pivottable.
                With ptTable
                    .ManualUpdate = True
                    .PivotFields("POS").Orientation = excel.XlPivotFieldOrientation.xlRowField
                    .PivotFields("SKU").Orientation = excel.XlPivotFieldOrientation.xlDataField()
                    .PivotFields("LINE_OVERALL_DISCOUNT").Orientation = excel.XlPivotFieldOrientation.xlDataField()
                    .Format(excel.XlPivotFormatType.xlReport2)
                    .ManualUpdate = False
                End With
            Catch ex As Exception
                MsgBox(ex.Message)
            End Try