[Pustik]

Надо указать в группировке все поля, заданные вами в выражении select, всех таблиц что-то типа того :

while select  InvoiceId,      
                  INVOICEDATE,    
                  DlvMode,
                  weight 
          from VendInvoiceJour
group by InvoiceId,INVOICEDATE,DlvMode,weight 
          where VendInvoiceJour.INVOICEDATE>=startdate && VendInvoiceJour.INVOICEDATE<=endDate

          join Party
          from VendTable
group by Party
          where VendTable.AccountNum ==VendInvoiceJour.InvoiceAccount 

          join Name          
               from    DirPartyTable
group by Name          
               where VendTable.Party == DirPartyTable.RecId

          join MarkupCode,         
               DeliveryTripId,
               DeliveryOrderId,
               SUM(Value)            
               from   MarkupTrans
               GROUP BY MarkupCode, MarkUpTrans.TRANSRECID ,MarkUpTrans.TRANSTableID, DeliveryTripId, DeliveryOrderId
               where MarkUpTrans.TRANSRECID == VendInvoiceJour.RecId
                     && MarkUpTrans.TRANSTableID == VendInvoiceJour.TableId 
        
          outer join  TripID,         
                Contractor
               from   DeliveryTrip
group by TripID,Contractor
               where MarkupTrans.DeliveryTripId == DeliveryTrip.TRIPID
    { info (InvoiceId) }