Error while cancel Purchase Order

Question

Hello everyone.
I'm trying to cancel a Purchase Order which has a Purchase Delivery Note.
First I cancel the Purchase Delivery Note and than I try to cancel the Purchase Order, but I'm having the following error: "The requested action is not supported for this object."
If I manually cancel the Purchase Delivery Note, I can successfully cancel the Purchase Order by code.
Here is the code I'm using:
Documents lDocumento = Globals.AddOn.ConexaoAuxiliar.GetBusinessObject(BoObjectTypes.oPurchaseDeliveryNotes);
lDocumento.GetByKey("DocEntry");//DocEntry is just an example
Documents lCancelamento = lDocumento.CreateCancellationDocument();
if (lCancelamento.Add() != 0)
     throw new Exception(Globals.AddOn.ConexaoAuxiliar.GetLastErrorDescription());
Then I try to cancel the Purchase Order:
Documents lDocumento = Globals.AddOn.ConexaoAuxiliar.GetBusinessObject(BoObjectTypes.oPurchaseOrders);
lDocumento.GetByKey("DocEntry");//just an example..
if (lDocumento.Cancel() != 0)//if can't cancel, try to close
     if (lDocumento.Close() != 0)//if can't close, show error..
          throw new Exception(Globals.AddOn.ConexaoAuxiliar.GetLastErrorDescription());
SAP 9 PL 10

Answer 1

Hi Leandro,
Sorry, I missed that bit. But that brings to mind, you create the cancellation document, but apparently you do not explicitly cancel the purchase delivery note.
Could you please test that ? So for example:
if (lCancelamento.Add() != 0)
  if (lDocumento.Close() != 0)
//etc.
Could you also please test commenting out the code that closes the purchase order, and then check from the B1 client that the delivery was closed and linked to a Returns document ?
Regards,
Johan