Error 1 Inconsistent accessibility: parameter type

[C# Programming]

I want to build something like this

http://www.codeproject.com/KB/aspnet/ChatApplication.aspx

However when using the example I try to build the chat app and get the error

Error 1 Inconsistent accessibility: parameter type 'ChatClient.IPAddressInfoEventArgs' is less accessible than delegate 'ChatClient.Configurator.IPChangeHandler' \EasyTalk\ChatClient\ChatClient\Configurator.cs 15 30 ChatClient

Any advice or examples of how to build a simple chat application using a web service.

Every google search presents many examples with very little explanation.

thanks for any advice