ASP.NET

LoadInfo l = new LoadInfo();
l.LoadFromSQL(Session["username"].ToString());

public void LoadFromSQL(string username)
   {
       SqlDataReader reader = null;
       reader = SqlMember.ExecuteReader("SELECT UserId FROM Members WHERE UserName=@username", username);
       m.LoadFromReader(reader);
   }

static public SqlDataReader ExecuteReader(string qs,string username)
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
        SqlCommand cmd = new SqlCommand(qs, conn);
        cmd.Parameters.Add(new SqlParameter ("@username","a"));
        conn.Open();
        if (cmd.ExecuteScalar() == null)
        {
            int i;
            i = 0;
        }
        return cmd.ExecuteReader();
    }

public void LoadFromReader(SqlDataReader reader)
    {
        this.UserId = (int)reader["UserId"];
        this.FirstName = (string)reader["FirstName"];
        this.LastName = (string)reader["LastName"];
        this.CityId = (int)reader["CityId"];
        this.CountryId = (int)reader["CountryId"];
        this.Mood = (byte)reader["Mood"];
    }

Invalid attempt to read when no data is present.