[racket] Access c based dll through ffi

Hello Friends,

I have make a little dll in visual studio :
[CODE_BEGIN]
#include <stdio.h>

extern "C"
{
  __declspec(dllexport) void DisplayHelloFromDLL()
  {
    printf ("Hello from DLL !\n");
  }
}
[CODE_END]

After I try to access it through ffi like this:
[CODE_BEGIN]
#lang racket

(require ffi/com
         ffi/unsafe
         ffi/unsafe/define
         ffi/winapi
         racket/string
         racket/format)

(define-ffi-definer define-dreamlog (ffi-lib "DreamLogging"))
[CODE_END]


But I get an 
ffi-lib: couldn't open "DreamLogging.dll" (Unknown error; errno=193)

So my question is: What should be the right structure for ffi for accepting it?

Yours,