Ошибка: variable is being used without being defined

// mPOH.cpp : Defines the entry point for the console application.
//
 
#include "stdafx.h"
#include <stdio.h>
#include <string.h>
#include <windows.h>
#include <io.h>
#include <stdlib.h>
#include <iostream>
#include <conio.h>
#include <C:\mPOOH\mPOOH\mPOOH.h>
 
using namespace std;
 
int _tmain(int argc, _TCHAR* argv[])
{   
    HINSTANCE hDll;
 
    if(argc<2) wprintf(L"to read help, type [name_of_program] -h");
    else
    {
        if(!wcscmp(argv[1], L"-l"))
        {
            hDll = LoadLibrary(LPCWSTR(argv[2]));
            cout << "Library load.\n";
            if(GetLastError()!=0) wprintf(L"error loading library\n");
        }
        if(!wcscmp(argv[1], L"-h")) wprintf(L"you want to read help\n");
    }
 
    int num_act;
 
    cout << "1 - CONCLUSION OF THE CONTAINED CURRENT CATALOGUE AND DELIVERY OF THE\n";
    cout << "INFORMATION ON CHARACTERISTICS OF THE SPECIFIED FILE\n";
    cout << "2 - FILE REMOVAL\n";
    cout << "3 - FILE RENAMING\n";
    cout << "4 - LIBRARY UNLOADING\n";
 
    cout << "Choose action: ";
    cin >> num_act;
 
    while (num_act != 4)
    {
        switch(num_act)
        {
        case 1: GetProcAddress(hDll, "INFO_FILE");
            break;
 
        case 2: GetProcAddress(hDll, "REMOVE_FILE");
            break;
 
        case 3: GetProcAddress(hDll, "RENAME_FILE");
            break;
        }
 
      break;
    }
    cout << "Choose action: ";
    cin >> num_act;
 
    if(num_act > 4)
    {
        FreeLibraryAndExitThread(hDll, NULL);
    }
    cout << "eee!!!!" << endl;
  }

MYPROC REMOVE_FILE = (MYPROC)GetProcAddress(hDll, "REMOVE_FILE");
    if (REMOVE_FILE)
    {
        cout << "Function load!!\n";
        REMOVE_FILE();
}

#include "mPOOH.h" 
#include <iostream>
 
#define MAXMODULE 50 
 
char module[MAXMODULE]; 
 
using namespace std;
 
extern "C" __declspec(dllexport) void RENAME_FILE() 
{
    GetModuleFileName(NULL, (LPTSTR)module, MAXMODULE);
 
    cout << "FILE RENAMING\n";
 
    char oldn[_MAX_PATH], newn[_MAX_PATH];
    int result3; 
        
    printf ("Enter the old filename: ");
    cin >> oldn; 
 
    printf ("Enter the new filename: ");
    cin >> newn; 
 
    result3 = rename (oldn, newn); 
 
    if (result3 == 0)
        printf ("File successfully renamed.\n"); 
    else
          printf("Unable to rename file");
} 
 
 
 
extern "C" __declspec(dllexport) void REMOVE_FILE() 
{
    GetModuleFileName(NULL, (LPTSTR)module, MAXMODULE);
 
    int value;
    char rem_name[_MAX_PATH]; 
 
    printf ("Enter file to remove: "); 
    cin >> rem_name;
 
    value = _unlink (rem_name); 
      
    if (value == 0) 
        printf ("Erased from disk\n", rem_name); 
    else
        printf("Unable to erase file\n");
 
}
 
 
 
extern "C" __declspec(dllexport) void INFO_FILE()
{
    GetModuleFileName(NULL, (LPTSTR)module, MAXMODULE);
    
    WIN32_FIND_DATA FindFileData;
    BY_HANDLE_FILE_INFORMATION FileInformation;
    HANDLE hFind;
    char filen[_MAX_PATH];
 
    hFind = FindFirstFile( /*(argv[1])*/ LPCWSTR(filen), &FindFileData);
    if (hFind == INVALID_HANDLE_VALUE) 
        printf ("FindFirstFile failed (%d)\n", GetLastError());
    else 
    {
        HANDLE hFile = CreateFile(
            /*argv[1]*/LPCWSTR(filen), GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, NULL);
 
        printf ("The first file found is %s\n", FindFileData.cFileName);
        GetFileInformationByHandle(hFile, &FileInformation );
        cout << "dwFileAttributes: " << int(FileInformation.dwFileAttributes) << endl;
        cout << "dwVolumeSerialNumber: " << int(FileInformation.dwVolumeSerialNumber) << endl;
        cout << "nFileSizeHigh: " << int(FileInformation.nFileIndexHigh) << endl;
        cout << "nFileSizeLow: " << int(FileInformation.nFileIndexLow) << endl;
        cout << "nNumberOfLinks: " << int(FileInformation.nFileSizeHigh) << endl;
        cout << "nFileIndexHigh: " << int(FileInformation.nFileSizeLow) << endl;
        cout << "nFileIndexLow: " << int(FileInformation.nNumberOfLinks) << endl;
 
        FindClose(hFind);
    }
}

#ifndef _mPOOH_H_
 
#define _mPOOH_H_ 
 
#include <iostream>
#include <stdio.h>
#include <windows.h> 
 
extern "C" __declspec(dllexport) void RENAME_FILE();
extern "C" __declspec(dllexport) void REMOVE_FILE();
extern "C" __declspec(dllexport) void INFO_FILE();
 
#endif