Implementing new Package failed.

[burnt pivot]

uhm.. not that experienced tbh, but I would try to console output the p.ReadUInt's and comment out the world.player stuff to see if that part and data you get works as expected

[royal tapir]

The packet length seems off.

On the server side it looks fine. ->

        public sealed class PlayerMobileExperience : Packet
        {
            public PlayerMobileExperience(PlayerMobile m)
                : base(0xFF, 7)
            {
                m_Stream.Write(m.Lvl);
                m_Stream.Write(m.Experience);
                Console.Out.WriteLine(m.Lvl);
                Console.Out.WriteLine(m.Experience);
            }
        }

[mellow rain]

There's a packet table where the length of all packets are defined. I don't know what the file name is called but it should be easy to find.

Also you need to define there if your packet has a fixed or variable length, but it looks like it's fixed

When the client freezes due to packets it's usually a mismatch between packet lengths. Check the read location of the StackDataReader in the client to see if you try to read too much or too little

Make sure that m.Lvl is actually written as a short for example