Hi all,
I had posted another query in this mailing list, but couldn't get any reply.
I had implemented an agenda observer and used it the following way.
iModel->SetMode(CAgnEntryModel::EClient);
TRAPD(error1,iModel->OpenL(_L("c:\\Documents\\AGENDA\\AGENDA")))
if(error1 != KErrNone)
   {
   delete iModel;
   iServer->CloseAgenda();
   User::Leave(error);

   }
iMyServer->WaitUntilLoaded();

Agenda = CAgnTestObserver::NewL();
CleanupStack::PushL(Agenda);
          // iModel->RegisterObserverL(_L("OBSERVERDLL"), Agenda);
TRAPD(err,iModel->RegisterObserverL(_L("OBSERVERDLL"), Agenda));
if(err == KErrNone)
{
   iEikonEnv->InfoMsg(_L("Observer no error."));
}
else
{
   iEikonEnv->InfoMsg(_L("Observer error."));
}
CleanupStack::Pop(5); // observer

and in the destructor i am deregistering it too.

My Observer class implementation is like this.
EXPORT_C CAgnTestObserver*CAgnTestObserver::NewL()
{
   CAgnTestObserver* self = new(ELeave) CAgnTestObserver();
   CleanupStack::PushL(self);
   self->ConstructL();
   CleanupStack::Pop();
   return (self);

}
CAgnTestObserver::CAgnTestObserver():iLogName(KNullLogFile)
{

}
CAgnTestObserver::~CAgnTestObserver()
{
   delete iMessageToInfoPrint;
   iFsSession.Close();
   iNotifier.Close();
   delete iCharConv;

}

CAgnObserver* CAgnTestObserver::CloneL()
{
   CAgnTestObserver* observer = CAgnTestObserver::NewL();
   observer->SetLogName(iLogName);
   return observer;

}

void CAgnTestObserver::StartObserving()
{
   _LIT(KStartedObserving, "Starting observing agenda file...");
   AppendToLogFileWithNewLineL(KStartedObserving);

}
void CAgnTestObserver::StopObserving()
{
   _LIT(KEndedObserving, "Finished observing agenda file...");
   AppendToLogFileWithNewLineL(KEndedObserving);

}   

void CAgnTestObserver::ConstructL()
   {
   User::LeaveIfError(iFsSession.Connect());
   User::LeaveIfError(iNotifier.Connect());

   iCharConv = CCnvCharacterSetConverter::NewL();
   CArrayFix<CCnvCharacterSetConverter::SCharacterSet>* arrayOfCharacterSetsAvailable = iCharConv->CreateArrayOfCharacterSetsAvailableL(iFsSession);
   CleanupStack::PushL(arrayOfCharacterSetsAvailable);
   iCharConv->PrepareToConvertToOrFromL(0x100012b6, *arrayOfCharacterSetsAvailable, iFsSession); // 0x100012b6 is KCharacterSetIdentifierCodePage1252
   iCharConv->SetReplacementForUnconvertibleUnicodeCharactersL(_L8("?"));
   CleanupStack::PopAndDestroy(); // arrayOfCharacterSetsAvailable
   }


void CAgnTestObserver::ExternalizeL(RWriteStream& aStream) const
   {
   aStream << iLogName;
   
   WriteEndMarkerL(aStream);
   }

void CAgnTestObserver::InternalizeL(RReadStream& aStream)
   {
   aStream >> iLogName;
   ReadEndMarkerL(aStream);

   iFsSession.Delete(iLogName);
   }

void CAgnTestObserver::Send(TInt aFunction, CAgnEntry* aEntry)
   {
//   __ASSERT_ALWAYS(aEntry, Panic(EAgnObsPanicNoAgendaEntry));

   switch (aFunction)
      {
      case ENotifyAddEntry:
         WriteEntryActionL(KEntryAdded, *aEntry);
         break;
      case ENotifyDeleteEntry:
         WriteEntryActionL(KEntryDeleted, *aEntry);
         break;
      case ENotifyUpdateEntry:
         WriteEntryActionL(KEntryUpdated, *aEntry);
         break;
      /*case ENotifyFetchEntry:
         WriteEntryAction(_L("Entry fetched: "),aEntry);
         break*/;
      default:
         {
         TBuf<200> buf;
         buf.Format(KUnhandledEntryFunc, aFunction);
         WriteEntryActionL(buf, *aEntry);
         break;
         }
      }
   }

void CAgnTestObserver::Send(TInt aFunction, CAgnTodoList* aTodoList)
   {
//   __ASSERT_ALWAYS(aTodoList, Panic(EAgnObsPanicNoAgendaToDo));

   switch (aFunction)
      {
      case ENotifyAddTodoList:
         WriteTodoListActionL(KToDoAdded, *aTodoList);
         break;
      case ENotifyDeleteTodoList:
         WriteTodoListActionL(KToDoDeleted, *aTodoList);
         break;
      case ENotifyUpdateTodoList:
         WriteTodoListActionL(KToDoUpdated, *aTodoList);
         break;
      /*case ENotifyFetchTodoList:
         WriteTodoListActionL(_L("TodoList fetched: "),aTodoList);
         break; */
      default:
         {
         TBuf<200> buf;
         buf.Format(KUnhandledToDoFunc, aFunction);
         WriteTodoListActionL(buf, *aTodoList);
         break;
         }
      }
   }



///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////

EXPORT_C void CAgnTestObserver::SetLogName(const TDesC& aLogName)
   {
   iLogName = aLogName;
   }

The start observing stop observing functions are getting called.
The agenda application also is working fine.
But i am not getting any events for agenda modifications/delete and additon through the send function of my observer.
what could be the reason.

A sppedy reply is hightly appreciated.
thanks for the time
arun