Postmessage not working with WH_GETMESSAGE-MFC

Hi,
I Have Installed A Hook With WH_GETMESSAGE On A DLL Using MFC.But When I Send Postmessage To My Parent Window It Is Not Received...

HWND hwndmain; //(Assigned The Value Of Main Window HWND)

static UINT snd=::RegisterWindowMessage(L"mainwnd_msg");

::PostMessage(hwndmain,snd,66,0);


The Same Message Is Declared In The Main Window To Receive The Registered Window Message And Added On register message event also But It Is Not Working Kindly Help Me I'm Not Able To Find What Is Happenning...

LRESULT CALLBACK msgProc(int ncode, WPARAM wparam, LPARAM lparam)

if(wparam=='A')

::PostMessage(mainwnd2,snd,66,0);

return CallNextHookEx(hk, ncode, wparam, lparam);