export of sqlite database in assets folder

I have a sqlite database in my assets folder. I want to export that file. So I do this:

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
            .permitAll().build();
    StrictMode.setThreadPolicy(policy);
    //
    File direct = new File(Environment.getExternalStorageDirectory()
            + "/Exam Creator");

    if (!direct.exists())
    {
        if (direct.mkdir())
        {
            // directory is created;
        }

    }
    exportDB();
    // importDB();

}

private void exportDB()
{
    // TODO Auto-generated method stub

    try
    {
        File sd = Environment.getExternalStorageDirectory();
        File data = Environment.getDataDirectory();

        if (sd.canWrite())
        {
            dbopenhelper.copyDataBase();
            String currentDBPath = dbopenhelper.DB_PATH
                    + dbopenhelper.DATABASE_NAME;
            String backupDBPath = "/BackupFolder/Prayers.db";
            File currentDB = new File(data, currentDBPath);
            File backupDB = new File(sd, backupDBPath);

            FileChannel src = new FileInputStream(currentDB).getChannel();
            FileChannel dst = new FileOutputStream(backupDB).getChannel();
            dst.transferFrom(src, 0, src.size());
            src.close();
            dst.close();
            Toast.makeText(getBaseContext(),
                    backupDB.toString() + "SUCCESS", Toast.LENGTH_LONG)
                    .show();

        }
    } catch (Exception e)
    {

        Toast.makeText(getBaseContext(), e.toString(), Toast.LENGTH_LONG)
                .show();

    }
}

to get the path of my currentDB, I first copy the database in my project using this method in my DBOpenHelper and by calling it in export method as you can see above.

public static void copyDataBase()
{
    try
    {

        InputStream input = context.getAssets().open(DATABASE_NAME);
        FileOutputStream output = new FileOutputStream(DB_PATH
                + DATABASE_NAME);
        byte[] data = new byte[1024];
        int buffer;
        while ((buffer = input.read(data)) != -1)
        {
            output.write(data, 0, buffer);
        }
        output.flush();
        output.close();
        input.close();
    } catch (IOException ex)
    {
        Log.e(LOGTAG, "Error in copying database...");
    }
}

but when I run it, I get Filenotfound exception. I debuged it and saw that after this line:

FileChannel src = new FileInputStream(currentDB).getChannel();

it goes to catch block. Does anyone know what is wrong?

Thanks in advance