SerializationException was UnHandled

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C#

Hello,

I am working on a project . I am programming in c# using Visual Studio 2008. It is a Client/Server chat based application. I am sending a class object over TCP for authentication and then UDP for further message passing. Everything works perfectly fine until a client logout . When a client logout I get the following error at the server:

SerializationException was UnHandled
The input stream is not a valid binary format. The starting contents (in bytes) are: 6C-6F-67-6F-75-74-24-61-7A-68-61-72-00-00-00-00-00 ...

The error come at the following line:
Commons.Data tmp = (Commons.Data)bf.Deserialize(ms);

The very same line is also run when the clients are sending messages to each other and it works perfectly fine then.

The following is a screenshot of the :

Console.WriteLine(e.StackTrace);
                    Console.WriteLine(e.Message);
                    Console.WriteLine(e.TargetSite);

The screenshot is at:
http://i48.tinypic.com/2q9g8qx.png[^]

The server keeps running properly even after this exception.