I did struggle to make this work, but sometimes the solution is more simple than you think it is

Go to UsePortalHandler.cs (wServer.networking.handlers)
Find HandleGuildPortal function
Find player.Reconnect(world); and replace with
Code:
player.Reconnect(world.GetInstance(player.Client));
Now go to UnrankedCommands.cs (wServer.realm.commands)
Find GhallCommand and replace it with this
Code:
class GhallCommand : Command    {
        public GhallCommand() : base("ghall") { }


        protected override bool Process(Player player, RealmTime time, string args)
        {
            if (player.GuildRank < 0)
            {
                player.SendError("You need to be in a guild.");
                return false;
            }


            var proto = player.Manager.Resources.Worlds["GuildHall"];
            var world = player.Manager.GetWorld(proto.id);
            player.Reconnect(world.GetInstance(player.Client));
            return true;
        }
    }
done, now just put the maps (attached) in your worlds folder and it should be working
make sure you have followed every step correctly before saying that you got an error