Unable to access SQLite Database form windows services

I have developed an ADD-in for outlook 2010. on outlook startup, ADD-in stored all the mail subjects in SQLite database.

Now i have to create a windows services that will also access same database, and post it on rest-based services. But I am getting an error.

Windows services is not able to access that database.

 static void Main()
    {
        //try
        //{
            //=======Connection string=============
        string dbfile = @"D:\testdatabase.db";

        sql_con = new SQLiteConnection
            ("Data Source= " + dbfile + ";Version=3;New=False;Compress=True;");
            //=======Open Connection=============
            sql_con.Open();
            //=======Create dataset and store value in dataset===================
            sql_cmd = sql_con.CreateCommand();
            string CommandText = "select * from mailbackup";
            DB = new SQLiteDataAdapter(CommandText, sql_con);
            //DS.Reset();
            DB.Fill(DS);
            //=======Store dataset value in text file============
            StringBuilder str = new StringBuilder();
            int rows = DS.Tables[0].Rows.Count;
            for (int i = 0; i < rows;i++ )
            {
                str.AppendLine(DS.Tables[0].Rows[i].ItemArray[0].ToString());
                str.AppendLine(DS.Tables[0].Rows[i].ItemArray[1].ToString());
                str.AppendLine(DS.Tables[0].Rows[i].ItemArray[2].ToString());
                str.AppendLine(DS.Tables[0].Rows[i].ItemArray[3].ToString());
                str.AppendLine(DS.Tables[0].Rows[i].ItemArray[4].ToString());
                str.AppendLine(DS.Tables[0].Rows[i].ItemArray[5].ToString());
                str.AppendLine(DS.Tables[0].Rows[i].ItemArray[6].ToString());
                str.AppendLine(DS.Tables[0].Rows[i].ItemArray[7].ToString());
                str.AppendLine(DS.Tables[0].Rows[i].ItemArray[8].ToString());
                StreamWriter sw = null;
                sw = new StreamWriter(AppDomain.CurrentDomain.BaseDirectory + "\\LogFile.txt", true);
                sw.WriteLine(DateTime.Now.ToString() + ": " + str.ToString());
                sw.Flush();
                sw.Close();
            }
                //=======Close Connection=============
                sql_con.Close();
            //storedata();
        //}
        //catch(System.Exception ex)
        //{

        //}
    }

I am getting an error

An unhandled exception of type 'Finisar.SQLite.SQLiteException' occurred in SQLite.NET.dll

Additional information: unsupported file format

it is working fine when we change the connection string

 sql_con = new SQLiteConnection
        ("Data Source= " + dbfile + ";Version=3;New=True;Compress=True;");

Create new database and open connection but after creating table using sqlite browser or SQLiteStudio, It start throwing the same error.