What did I do wrong?
Exception:
System.NullReferenceException: Object reference not set to an instance of an object.
at Server.Services.UOBattleCards.Gumps.GumpUtility.LoadCardGump(PlayerMobile user, CardInfo card, BaseGump gump, Int32 x, Int32 y, MatchInfo game)
at Server.Services.UOBattleCards.Gumps.BaseCardGump.CardLayout(PlayerMobile user, CardInfo card, Int32 X, Int32 Y)
at Server.Services.UOBattleCards.Gumps.BaseCardGump.AddGumpLayout()
at Server.Gumps.BaseGump.Refresh(Boolean recompile, Boolean close)
at Server.Gumps.BaseGump.OnResponse(NetState state, RelayInfo info)
at Server.Network.PacketHandlers.DisplayGumpResponse(NetState state, PacketReader pvSrc)
at Server.Network.MessagePump.HandleReceive(NetState ns)
at Server.Network.MessagePump.Slice()
at Server.Core.Main(String[] args)