"All solutions are 100% Java based and therefore this service can be used on any platform with an installed Java Runtime Environment, including mobile phones."
The fact that it needs Java is probably the reason it doesn't work and is nothing to do with the Http library.
That 100%Java statement on the first page of the Toonel site is wrong, although I took it at face value
Your .NETversion of Toolnet works by trapping port 8080 on your local IP address 127.0.0.1 and pretending to be a proxy server. Presumably it does this to do the local data decompression. It looks like whatever this local proxy does is not compatible with the HTTP library.