Some Help Please Please

Hi! I found this code in i'm going to hook another process using SetWindowsHookEx, and send back back to vb6 here is code:

Code:

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//HookDemo.cpp
#include <windows.h>
#include "WINUSER.H"   

/*---------------------------------------------
          Shared Variables
This data is shared between both prcesses.  The
VB App has access to these variables through the
function SetSharedData
---------------------------------------------*/
#pragma data_seg(".shared")
        HHOOK        hmsgHooks = 0;                // Hook handle for WH_GETMESSAGE
#pragma data_seg()
#pragma comment(linker, "/SECTION:.shared,RWS")

typedef void (__stdcall *funcp)(long);
funcp VBCallback;
//---------------------------------------------
// Global Variables, specific to each process
//---------------------------------------------
        HINSTANCE        hInstance;        // Global instance handle for DLL

//--------------------------------------------
//        DLL entry-point
//--------------------------------------------
BOOL WINAPI DllMain(
    HINSTANCE hinstDLL,  // handle to DLL module
    DWORD fdwReason,    // reason for calling function
    LPVOID lpvReserved )  // reserved
{
    // Perform actions based on the reason for calling.
    switch( fdwReason )
    {
        case DLL_PROCESS_ATTACH:
        // Initialize once for each new process.
        // Return FALSE to fail DLL load.
                        hInstance = hinstDLL;//save dll handle for each process
            break;
       
        case DLL_THREAD_ATTACH:
        // Do thread-specific initialization.
            break;

        case DLL_THREAD_DETACH:
        // Do thread-specific cleanup.
            break;

        case DLL_PROCESS_DETACH:
        // Perform any necessary cleanup.
            break;
    }
    return TRUE;  // Successful DLL_PROCESS_ATTACH.
}

LRESULT CALLBACK GetMsgProc(int nCode, WPARAM wParam, LPARAM lParam);

__declspec(dllexport) int _stdcall InstallFilterDLL(DWORD dwThreadId, long lpCallback)
{
        if (hmsgHooks==0)
                        VBCallback = (funcp)lpCallback;
                        hmsgHooks = SetWindowsHookEx(WH_GETMESSAGE,(HOOKPROC) GetMsgProc, (HINSTANCE) hInstance, dwThreadId);
                                                       
                                ::Sleep(1000L);
                if (hmsgHooks==0) return GetLastError();
        return 0;
}

 __declspec(dllexport) int UnInstallFilterDLL(void)
{
        LRESULT result;
        if (hmsgHooks != 0){
                result = UnhookWindowsHookEx(hmsgHooks);
                if (result == 0) return GetLastError();
                hmsgHooks = 0;
        }
        return 0;
}

LRESULT CALLBACK GetMsgProc(int nCode, WPARAM wParam, LPARAM lParam)
{
        MSG *lpMsg;
        //return immediately for negative nCodes
        if (nCode >= 0){
                if (nCode==HC_ACTION){
                        lpMsg = (MSG *) lParam;
                        if(lpMsg->message == WM_COMMAND)
                        {
                                VBCallback((short)lpMsg->hwnd);
                        }
                }//end if nCode==Action
        }//end if nCode >=0                       
        return(CallNextHookEx(hmsgHooks, nCode, wParam, lParam));
}


 __declspec(dllexport) int fDLL(void)
{
        VBCallback((short)hInstance);
        return 0;
}

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how come it crash everytime wm_command is clicked? what am i doing wrong?

i know that function send to vb6 work because i move that function installfilterdll and make send back vb6 nothin wrong, so......

please help
thank thousand