[Lord_Helmchen]

I found some more information on the error in the log files:

compression_overflow.log

02.08.2008 20:28:46 Warning: Compression buffer overflowed on packet 0xDD ('DisplayGumpPacked') (length=0)
   at Server.Network.Packet.InternalCompile(Boolean compress)
   at Server.Network.Packet.Compile(Boolean compress, Int32 ByRef length)
   at Server.Network.NetState.Send(Server.Network.Packet p)
   at Server.Gumps.Gump.SendTo(Server.Network.NetState state)
   at Server.Mobile.SendGump(Server.Gumps.Gump g, Boolean throwOnOffline)
   at Server.Mobile.SendGump(Server.Gumps.Gump g)
   at Server.Gumps.AdminGump.Admin_OnCommand(Server.Commands.CommandEventArgs e)
   at Server.Commands.CommandSystem.Handle(Server.Mobile from, System.String text, MessageType type)
   at Server.Mobile.DoSpeech(System.String text, System.Int32[] keywords, MessageType type, Int32 hue)
   at Server.Mobiles.PlayerMobile.DoSpeech(System.String text, System.Int32[] keywords, MessageType type, Int32 hue)
   at Server.Network.PacketHandlers.UnicodeSpeech(Server.Network.NetState state, Server.Network.PacketReader pvSrc)
   at Server.Network.MessagePump.HandleReceive(Server.Network.NetState ns)
   at Server.Network.MessagePump.Slice()
   at Server.Core.Main(System.String[] args)

null_send.log

02.08.2008 20:28:46 Client: 192.168.191.24: null buffer send, disconnecting...
   at Server.Network.NetState.Send(Server.Network.Packet p)
   at Server.Gumps.Gump.SendTo(Server.Network.NetState state)
   at Server.Mobile.SendGump(Server.Gumps.Gump g, Boolean throwOnOffline)
   at Server.Mobile.SendGump(Server.Gumps.Gump g)
   at Server.Gumps.AdminGump.Admin_OnCommand(Server.Commands.CommandEventArgs e)
   at Server.Commands.CommandSystem.Handle(Server.Mobile from, System.String text, MessageType type)
   at Server.Mobile.DoSpeech(System.String text, System.Int32[] keywords, MessageType type, Int32 hue)
   at Server.Mobiles.PlayerMobile.DoSpeech(System.String text, System.Int32[] keywords, MessageType type, Int32 hue)
   at Server.Network.PacketHandlers.UnicodeSpeech(Server.Network.NetState state, Server.Network.PacketReader pvSrc)
   at Server.Network.MessagePump.HandleReceive(Server.Network.NetState ns)
   at Server.Network.MessagePump.Slice()
   at Server.Core.Main(System.String[] args)

If I understood that correctly then Zlib return the "Buffer Error" when it is passed an empty buffer. And that this behavior is new since a few versions.