Error while Trying to Hook "TerminateProcess" Function. Target Process crashes. Can anyone help me?

Debugging with visual studio 2005 The following Error Displayed :

Unhandled exception at 0x00000000 in procexp.exe: 0xC0000005: Access violation reading location 0x00000000.

And Thread Information:

2704 Win32 Thread 00000000 Normal 0

extern "C" VDLL2_API BOOL WINAPI MyTerminateProcess(HANDLE hProcess,UINT uExitCode)
{
     SetLastError(5);
     return FALSE;
}

FARPROC HookFunction(char *UserDll,FARPROC pfn,FARPROC HookFunc) 

{
    DWORD dwSizeofExportTable=0;
    DWORD dwRelativeVirtualAddress=0;
    HMODULE hm=GetModuleHandle(NULL);
    FARPROC pfnOriginalAddressToReturn;
    PIMAGE_DOS_HEADER pim=(PIMAGE_DOS_HEADER)hm;
    PIMAGE_NT_HEADERS pimnt=(PIMAGE_NT_HEADERS)((DWORD)pim + 
(DWORD)pim->e_lfanew); 
    PIMAGE_DATA_DIRECTORY 
pimdata=(PIMAGE_DATA_DIRECTORY)&(pimnt->OptionalHeader.DataDirectory);

    PIMAGE_OPTIONAL_HEADER pot=&(pimnt->OptionalHeader);
    PIMAGE_DATA_DIRECTORY 
pim2=(PIMAGE_DATA_DIRECTORY)((DWORD)pot+(DWORD)104);
    dwSizeofExportTable=pim2->Size;
    dwRelativeVirtualAddress=pim2->VirtualAddress;
    char *ascstr;
    PIMAGE_IMPORT_DESCRIPTOR 
pimexp=(PIMAGE_IMPORT_DESCRIPTOR)(pim2->VirtualAddress + (DWORD)pim);
    while(pimexp->Name)
    {
        ascstr=(char *)((DWORD)pim + (DWORD)pimexp->Name);
        if(strcmpi(ascstr,UserDll) == 0)
        {
            break;
        }
        pimexp++;
    }
    PIMAGE_THUNK_DATA 
pname=(PIMAGE_THUNK_DATA)((DWORD)pim+(DWORD)pimexp->FirstThunk);
    LPDWORD lpdw=&(pname->u1.Function);
    DWORD dwError=0;
    DWORD OldProtect=0;
    while(pname->u1.Function)
    {
        if((DWORD)pname->u1.Function == (DWORD)pfn)
        {
            lpdw=&(pname->u1.Function);

VirtualProtect((LPVOID)lpdw,sizeof(DWORD),PAGE_READWRITE,&OldProtect);


            pname->u1.Function=(DWORD)HookFunc;

VirtualProtect((LPVOID)lpdw,sizeof(DWORD),PAGE_READONLY,&OldProtect);

            return pfn;
        }
        pname++;

    }
    return (FARPROC)0;
}


FARPROC CallHook(void) 
{
        HMODULE hm=GetModuleHandle(TEXT("Kernel32.dll"));
    FARPROC fp=GetProcAddress(hm,"TerminateProcess");
    HMODULE hm2=GetModuleHandle(TEXT("vdll2.dll"));
    FARPROC fpHook=GetProcAddress(hm2,"MyTerminateProcess");

    dwAddOfTerminateProcess=HookFunction("Kernel32.dll",fp,fpHook);
    if(dwAddOfTerminateProcess == 0)
    {
        MessageBox(NULL,TEXT("Unable TO Hook Function."),TEXT("Parth"),MB_OK);
    }
    else
    {
        MessageBox(NULL,TEXT("Success Hooked."),TEXT("Parth"),MB_OK);
    }
    return 0;
}

Thanks in advance for any help.

004118AC mov esi,esp
004118AE push 0
004118B0 mov eax,dword ptr [hProc]
004118B3 push eax
004118B4 call dword ptr[__imp__TerminateProcess@8(4181E4h)]
004118BA cmp esi,esp

esi returned zero. why ?

Don't write this kind of code yourself. Use the Detours library from Microsoft Research.