The error message clearly states the problem. Your MSMQ queue reader has not implemented the correct formatter. It is very important for the code to know in which format will the queue object be read.
Below is the sample code, implement the same as per your data type:
MessageQueue queue = new MessageQueue(@".\MyQueue");
System.Messaging.Message msg = new System.Messaging.Message();
msg = queue.Receive();
msg.Formatter = new System.Messaging.XmlMessageFormatter(new String[] { "System.String,mscorlib" });
Hope that helps.