>  I am also having the same problem.
> see message  "Sending a message from one app to another on NT" dated 18/7/97

> I have tried DDE_EXECUTE, WM_COPYDATA and what you have done, to no success

> >I am using Visual C++ 4.2 and Windows NT.  I am programming with the MFC.
> >I am trying to send a message from one app to another.  I have used the
> >Win32 API PostMessage and SendNotifyMessage using HWND_BROADCAST for the
> >first parameter to send the message.  I placed the message handler in
> >CMainFrame and used ON_MESSAGE in the message map.  The message does not
> >appear to be getting to it's destination.  Any advice would be greatly
> >appreciated.  Thank you.

>PostMessage with a user-defined message or SendMessage with WM_COPYDATA
>work fine.  First you have to control the receiving app's window class
>name by calling AfxRegisterClass in InitInstance and setting the
>cs.lpszClass parameter in the mainframe's PreCreateWindow.  Check it
>with Spy++ to make sure you have set the mainframe's class name.

>Then the sending app does:
>#define WM_MY_MESSAGE (WM_APP + 1234)
> CWnd* pOtherApp = FindWindow(TARGET_APP_WINCLASS_STRING, 0);
> if (pOtherApp)
> {  pOtherApp->PostMessage(WM_MY_MESSAGE, n1, n2);
> -- or --
>    pOtherApp->SendMessage(WM_COPYDATA, (WPARAM)m_hWnd, (LPARAM)&cds);
> }

>and the receiving app uses ON_MESSAGE in the mainframe message map (put
>it outside of the class wizard comments, just before END_MESSAGE_MAP().