User defined message , exception at handler's return

[Timbk]

Hello, Im using a dialog based app (VC++ 6), with a main dialog and his child dialog (modals dialogs).
And i have to use a user defined message to send a message to the parent dialog. When i'm debugging, in the handler of this message (in the parent dialog) i get this exception in the return sentence "Unhandled exception in Myapp.exe (MFC42D.DLL):0xc0000005: Acces Violation


Parent dialog header, declaration of Handler:

           .
           .	
	afx_msg LRESULT OnMsjGuardarConfig(WPARAM wParam, LPARAM lParam);
           .
           .

Parent dialog header, Declared Mesagge map:

           .
           .
	afx_msg void OnMsjGuardarConfig();
           .
           .

Parent dialog source, file Message map:

           .
           .
	ON_MESSAGE(WM_MsjGuardarConfig, OnMsjGuardarConfig)
           .
           .

Parent dialog source, file definition of the handler:

LRESULT CCalibracionDlg::OnMsjGuardarConfig(WPARAM wParam, LPARAM lParam)
{
  //i do some stuffs 
return 0; // ==> here is exception !!!!
}

Defining the user defined message in StdAfx.h:

           .
           .
#define WM_MsjGuardarConfig WM_USER+1 // 
           .
           .

Posting the message in the child dialog:

void CConfiguracionDlg::OnBUTTONGuadar() 
{
	GetParent()->;PostMessage(WM_MsjGuardarConfig,NULL,NULL); //
}

Probably is some newbie problem , but i can't fix it until now.
Thanks in advance!!