problem receiving data on server

hello, good day! i am currently working on a project that requires me to create a server and clients that send and receive messages to each other. I have a server that servers to receive client messages, inside of it looks something like this.. Byte[] bufferUpdate = new Byte[1024]; client.Receive(bufferUpdate); //where client is the socket MemoryStream ms = new MemoryStream(bufferUpdate); BinaryFormatter bf1 = new BinaryFormatter(); ms.Position = 0; update Collection = (update) bf1.Deserialize(ms); the data i send to the server on this scenario is gotten from this code MemoryStream ms = new MemoryStream(); BinaryFormatter bf1 = new BinaryFormatter(); bf1.Serialize(ms, (new update(new ArrayList(), new ArrayList()))); Byte[] outbytes = ms.ToArray(); ns.Write(outbytes,0,outbytes.Length); //where ns is the netstream ////// error happens at the deserialize on the server side. this is the exact error message shown An unhandled exception of type 'System.IO.FileNotFoundException' occurred in mscorlib.dll Additional information: File or assembly name POOLE, or one of its dependencies, was not found. ////// the update on the client and the server side is of the same .cs file i believe even if i send arraylists the problem still persists so far, all the codes i see only send string messages converted into bytes, is my code not applicable to objects? i need to send objects and then change them into files on the server side. can anyone please kindly help me. thanks