This looks to me like you probably have a .NET Framework Security settings issue. One of the design aims of .NET was to provide security levels that are impossible to achieve in non-managed code and the security settings can be tuned to achieve different levels of security appropriate to different environments.
You need to increase the permissions that B4PPC runs under to allow it to access the Internet. I am not even going to try to advise you on how to do this and the exact way of achieving it is different under .NET 1.1 and .NET 2.0. I suggest that you Google around for ".NET security" or ".NET permissions" and see what you come up with.