Assertn, that link takes u to another mirror of suprnova. Try this one:
http://server.mesi.com.ar:81/061.html

EDIT: If that link doesnt work (I hope it does), I can email you the torrent file. Just tell me your email address and I'll send it to ya ASAP. And Assertn, that Sonic series that has the green hedgehog is the Sonic Underground series. I believe that green hedgehog is Sonic's brother called Mania and he also has a sister called Sonia. The three of them of their own rock group or something like that. The suprnova site also has the Underground series as well. Just hope the link I posted works.