problem about with jni

I want to learn call a c code with jni in android.It's compiling.But it doesn't work.
This is my Android.mk file:

This is my C source code:

#include "stdio.h"
#include <jni.h>

JNIEXPORT void JNICALL Java_com_WebOynatici_WebOynaticiActivity_DosyayaYaz(JNIEnv * env,jobject obj){
char * html2;
html2="<!DOCTYPE html>\
            <html>\
            <head>\
            <body>\
            <object\
                data=\
            http://www.youtube.com/embed/6nFKPVfDrgU?feature=player_detailpage\
                width=\
            400 height=\
                300\
            >\
                <param value=\
            http://www.youtube.com/embed/6nFKPVfDrgU?feature=player_detailpage\
                >\
                <embed\
                src=\
                http://www.youtube.com/embed/6nFKPVfDrgU?feature=player_detailpage\
                type=\
                application/x-shockwaqvw-flash\
                width=\
                200\ height=\
                200\
            >\

</object>\
            </body>\
            </head>\
            </html>"; 
FILE * dosya;
dosya=fopen("mnt/sdcard/Res/object.html","wb");
fwrite(html2,1,strlen(html2),dosya);
}

And this is my java code:

package com.WebOynatici;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.widget.Toast;

public class WebOynaticiActivity extends Activity {
    WebView WEB;
    String klasor="mnt/sdcard/Res";
    String adres="mnt/sdcard/Res/object.html";
    public native void DosyayaYaz();
    static{
        
        System.loadLibrary("WebOynatici");
        
    }
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
        WebOynaticiActivity Yen=new WebOynaticiActivity();
        Yen.DosyayaYaz();
        setContentView(R.layout.main);
        WEB=(WebView)findViewById(R.id.Web);
        WEB.getSettings().setJavaScriptEnabled(true);;
        WebSettings webSettings = WEB.getSettings();
        webSettings.setJavaScriptEnabled(true);
        WEB.addJavascriptInterface(new JavaScriptInterface(this), "MyAndroid");
        WEB.setWebChromeClient(new WebChromeClient());
        WEB.loadUrl(adres);
    }
    public class JavaScriptInterface {
        Context mContext;
        JavaScriptInterface(Context c) {
            mContext = c;
        }
        public void receiveValueFromJs(String str) {
            Toast.makeText(mContext, "Received Value from JS: " + str,Toast.LENGTH_SHORT).show();
          }
   }
  
}

And i am working with Eclipse on Windows platform.
Where is my error?Thank you for your helps