Dim hierFilter As HierarchyFilter - User defined type not defined.

Hi all.

Used versions - QC8 and Excel 2007.

I am trying to display the total number of requiremnts in a folder. For this I have the bellow code.

Sub ReqNo ()

 On Error GoTo Err_Handler
    

   Dim reqF As ReqFactory
   
    Dim hierFilter As HierarchyFilter
    Dim reqHierL As HierarchySupportList, reqL As List
    Dim rq As Req

    Set TDConnection = CreateObject("TDApiOle80.TDConnection")

.....connection

.....log in

    Set reqF = TDConnection.ReqFactory
    Set hierFilter = reqF.Filter
    hierFilter("RQ_FATHER_ID") = 18
   
    hierFilter.KeepHierarchical = True
 

    Set reqHierL = hierFilter.NewList

    MsgBox (CStr(reqHierL.Count))

..........

When I try to run the code I got an error message at the line with Dim hierFilter As HierarchyFilter  - User defined type not defined.

What could be the issue?

Thanks in advance!

Vincent