why my main process exit with erro

#include <windows.h>
#include <tlhelp32.h>
#include <iostream.h>

typedef struct _RemoteParam 
{
	char szMsg[12];        
	DWORD dwMessageBox;
} RemoteParam, * PRemoteParam;

typedef int (__stdcall * PFN_MESSAGEBOX)(HWND, LPCTSTR, LPCTSTR, DWORD);

static DWORD WINAPI threadProc(LPVOID lParam)
{
	RemoteParam* pRP = (RemoteParam*)lParam;
	PFN_MESSAGEBOX pfnMessageBox;
	pfnMessageBox = (PFN_MESSAGEBOX)pRP-&gt;dwMessageBox;
	pfnMessageBox(NULL, pRP-&gt;szMsg, pRP-&gt;szMsg, 0);
	ExitThread(0);
	return 0;
}
static void afterthread(void)
{       
}
bool enableDebugPriv()
{
    HANDLE hToken;
    LUID sedebugnameValue;
    TOKEN_PRIVILEGES tkp;
  
    if (!OpenProcessToken(GetCurrentProcess(), 
        TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &amp;hToken)) {
        return false;
    }
    if (!LookupPrivilegeValue(NULL, SE_DEBUG_NAME, &amp;sedebugnameValue)) {
        CloseHandle(hToken);
        return false;
    }
    tkp.PrivilegeCount = 1;
    tkp.Privileges[0].Luid = sedebugnameValue;
    tkp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
    if (!AdjustTokenPrivileges(hToken, FALSE, &amp;tkp, sizeof(tkp), NULL, NULL)) {
        CloseHandle(hToken);
        return false;
    }
    return true;
}
DWORD processNameToId(LPCTSTR lpszProcessName)
{
	HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
	PROCESSENTRY32 pe;
	pe.dwSize = sizeof(PROCESSENTRY32);
	if (!Process32First(hSnapshot, &amp;pe)) {
		MessageBox(NULL, 
			"The frist entry of the process list has not been copyied to the buffer", 
			"Notice", MB_ICONINFORMATION | MB_OK);
		return 0;
	}
	while (Process32Next(hSnapshot, &amp;pe)) {
		if (!_stricmp(lpszProcessName, pe.szExeFile)) {
			return pe.th32ProcessID;
		}
	}
	return 0;
}
void main(int argc, char* argv[])
{
	const DWORD dwThreadSize = (LPBYTE)(afterthread)-(LPBYTE)(threadProc);
	DWORD dwWriteBytes;
	void* pRemoteThread;
	RemoteParam* pRemoteParam;
	HANDLE hRemoteThread;
	HANDLE hTargetProcess;
	enableDebugPriv();
	std::cout &lt;&lt; "Please input the name of target process !" &lt;&lt; std::endl;
	char szExeName[MAX_PATH] = { 0 };
	std::cin &gt;&gt; szExeName;
	DWORD dwProcessId = processNameToId(szExeName);
	if (dwProcessId == 0) {
		MessageBox(NULL, "The target process have not been found !",
			"Notice", MB_ICONINFORMATION | MB_OK);
		return ;
	}
	__try{
		hTargetProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, dwProcessId);
		if (!hTargetProcess) {
			MessageBox(NULL, "Open target process failed !", 
				"Notice", MB_ICONINFORMATION | MB_OK);
			return ;
		}
		pRemoteThread = VirtualAllocEx(hTargetProcess, 0, 
			dwThreadSize, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
		if (!pRemoteThread) {
			MessageBox(NULL, "Alloc memory in target process failed !", 
				"notice", MB_ICONINFORMATION | MB_OK);
			return ;
		}
		if (!WriteProcessMemory(hTargetProcess, 
			pRemoteThread, &amp;threadProc, dwThreadSize, 0)) {
				MessageBox(NULL, "Write data to target process failed !", 
					"Notice", MB_ICONINFORMATION | MB_OK);
				return ;
		}
		RemoteParam remoteData;
		ZeroMemory(&amp;remoteData, sizeof(RemoteParam));
		HINSTANCE hUser32 = LoadLibrary("User32.dll");
		remoteData.dwMessageBox = (DWORD)GetProcAddress(hUser32, "MessageBoxA");
		strcpy(remoteData.szMsg, "Hello\0");
		pRemoteParam = (RemoteParam*)VirtualAllocEx(
			hTargetProcess , 0, sizeof(RemoteParam), MEM_COMMIT, PAGE_READWRITE);
		if (!pRemoteParam) {
			MessageBox(NULL, "Alloc memory failed !", 
				"Notice", MB_ICONINFORMATION | MB_OK);
			return ;
		}
		if (!WriteProcessMemory(hTargetProcess ,
			pRemoteParam, &amp;remoteData, sizeof(remoteData), 0)) {
				MessageBox(NULL, "Write data to target process failed !", 
					"Notice", MB_ICONINFORMATION | MB_OK);
				return ;
		}
		hRemoteThread = CreateRemoteThread(
			hTargetProcess, NULL, 0, (DWORD (__stdcall *)(void *))pRemoteThread, 
			pRemoteParam, 0, &amp;dwWriteBytes);
		if (!hRemoteThread) {
			MessageBox(NULL, "Create remote thread failed !", "Notice",  MB_ICONINFORMATION | MB_OK);
			return ;
		}
		WaitForSingleObject(hRemoteThread,INFINITE);
	}
	__finally
	{
		VirtualFreeEx(hTargetProcess,pRemoteThread,0,MEM_RELEASE);
		VirtualFreeEx(hTargetProcess,pRemoteParam,0,MEM_RELEASE);
		CloseHandle(hRemoteThread);
	}
	return ;
}
</iostream.h></tlhelp32.h></windows.h>