Chat Application problem (UDP)

Question

Hi , Initially I was creating a Chat program with both the server side and client side in ASP.Net Win forms (C#) They were working great, but I had to change the client side to a web form. I had to do minor adjustments and it compiled correctly. (using UDPClient) However, in terms of communication, the web form (client side) can send data to the server side but when the server side tries to send data to the client side, I received this error an unhandled exception of type system.runtime.serialization.serializationexception occurred in unknown module. additional information: the type system.web.httpexception in assembly system.web, version1.0.5000.0,culture=neutral,publickeytoken=b03f5f7f11d50a3a is not marked as serializable The source codes are similar to the ones in this link http://www.vbip.com/books/1861007353/chapter_7353_05.asp Please help!