Posting Key Event, it works but...

Hi all,
I have written a class to post some keyEvents, it has a public method to do it,

now I want to post a string of keys,  i.e.  01234567891, the length of this string is 11,
the first ten of digist are posted successfully but the last digit can't be posted without any error,...
I just see 0123456789 on screen, the last digit (1) can't be posted,

Why? is there any buffer?

here is my public method of KeyPoster ActiveObject :

++++++++++++++++++++
void CKeyEventPoster::StartPostingKeyEvents(TUint aCode, TInt aModifier, TInt aRepeat, TInt aScanCode )
{

   TWsEvent event;
   TInt iForegroundWinGroup = iWsSession.GetFocusWindowGroup();

        event.SetType(EEventKeyDown);
        event.SetTimeNow();
        event.Key()->iCode = aCode;
        event.Key()->iModifiers = aModifier;
        event.Key()->iRepeats = aRepeat;
        event.Key()->iScanCode = aScanCode;
        iWsSession.SendEventToWindowGroup(iForegroundWinGroup, event);

        event.SetType(EEventKey);
        event.SetTimeNow();
        event.Key()->iCode = aCode;
        event.Key()->iModifiers = aModifier;
        event.Key()->iRepeats = aRepeat;
        event.Key()->iScanCode = aScanCode;
        iWsSession.SendEventToWindowGroup(iForegroundWinGroup, event);

        event.SetType(EEventKeyUp);
        event.SetTimeNow();
        event.Key()->iCode = aCode;
        event.Key()->iModifiers = aModifier;
        event.Key()->iRepeats = aRepeat;
        event.Key()->iScanCode = aScanCode;
        iWsSession.SendEventToWindowGroup(iForegroundWinGroup, event);
}
+++++++++++++++

and I call it in this way:

               iKeyEventPoster -> StartPostingKeyEvents('0' ,0, 0, EStdKeyNull);
               iKeyEventPoster -> StartPostingKeyEvents('1' ,0, 0, EStdKeyNull);
               iKeyEventPoster -> StartPostingKeyEvents('2' ,0, 0, EStdKeyNull);
               iKeyEventPoster -> StartPostingKeyEvents('3' ,0, 0, EStdKeyNull);
               iKeyEventPoster -> StartPostingKeyEvents('4' ,0, 0, EStdKeyNull);
               iKeyEventPoster -> StartPostingKeyEvents('5' ,0, 0, EStdKeyNull);
               iKeyEventPoster -> StartPostingKeyEvents('6' ,0, 0, EStdKeyNull);
               iKeyEventPoster -> StartPostingKeyEvents('7' ,0, 0, EStdKeyNull);
               iKeyEventPoster -> StartPostingKeyEvents('8' ,0, 0, EStdKeyNull);
               iKeyEventPoster -> StartPostingKeyEvents('9' ,0, 0,
EStdKeyNull);
              iKeyEventPoster -> StartPostingKeyEvents('1' ,0, 0,
EStdKeyNull);

++++++++++++++++++++
the red line doesn't work,...
Why?