C / C++ / MFC

BOOL CBtnIconDlg::OnInitDialog()
{

        HICON hIcon = AfxGetApp()->LoadIcon(IDI_ICON1);
	
	AfxMessageBox(ErrorMsg());//here i get GetLastError =0 (The operation completed successfully.)
	if(hIcon)
	{
		//ok valid icon found
	}
	else
	{
		AfxMessageBox(_T("NULL hIcon"));//this not popup
	}
		
	m_btn.SetIcon(hIcon);	
	AfxMessageBox(ErrorMsg());//here i get GetLastError =87 (The parameter is incorrect.)
	
	HICON icon =NULL;
	HINSTANCE	hInstResource	= NULL;	
	hInstResource = AfxFindResourceHandle(MAKEINTRESOURCE(IDI_ICON2), RT_GROUP_ICON);
	
	AfxMessageBox(ErrorMsg());//here i get GetLastError =0 (The operation completed successfully.)

	if(hInstResource)
	{
		//ok valid hInstResource found
	}
	else
	{
		AfxMessageBox(_T("hInstResource null"));//this not popup
	}
	
	icon = (HICON) LoadImage(hInstResource,
							MAKEINTRESOURCE(IDI_ICON2),
							IMAGE_ICON,
							16,
							16,
							LR_DEFAULTCOLOR); 

	
	AfxMessageBox(ErrorMsg());//here i get GetLastError =0 (The operation completed successfully.)
	if(icon )
	{
		//valid icon 
	}
	else
	{
		AfxMessageBox(_T("NULL icon "));//this not popup
	}
		
	m_btn2.SetIcon(icon);
	
	AfxMessageBox(ErrorMsg());//here i get GetLastError =87 (The parameter is incorrect.)

        return TRUE;
}

CString CBtnIconDlg::ErrorMsg()
{
	CString ret_msg=_T("");

	LPVOID lpMsgBuf;
	HRESULT hr;

	hr = GetLastError();

	ret_msg.Format(_T("%d :: "),GetLastError());
	
	FormatMessage( 
		FORMAT_MESSAGE_ALLOCATE_BUFFER | 
		FORMAT_MESSAGE_FROM_SYSTEM | 
		FORMAT_MESSAGE_IGNORE_INSERTS,
		NULL,
		hr,
		0, // Default language
		(LPTSTR) &lpMsgBuf,
		0,
		NULL 
	);

	ret_msg+=(LPCTSTR)lpMsgBuf;	
	LocalFree( lpMsgBuf);

	return ret_msg;
}

void StartEXE (String^ path)
{
TCHAR prog[] = TEXT("C:\\...\\...."); // Programpath

string p ;
MarshalString(path, p);
std::string str= p;
TCHAR *param=new TCHAR[str.size()+1];
param[str.size()]=0;

const TCHAR open[] = TEXT("runas")
ShellExecute( NULL, open, prog, param, NULL, SW_SHOWNORMAL );
}

void MarshalString ( String ^ s, string& os )
        {
        using namespace Runtime::InteropServices;
        const char* chars =
        (const char*)(Marshal::StringToHGlobalAnsi(s)).ToPointer();
        os = chars;
        Marshal::FreeHGlobal(IntPtr((void*)chars));
        }