Well, first of all, this is Mac. There are no AV programs. Second of all, yeah Mac has a really tight firewall that might be interfereing. One problem. You can't unblock JAR's, only .app's. Until Technic is remade into an app, you can't pass it through the firewall.
Also, I don't think thats the problem anyway, I think the problem is that "none" isn't a URL. I'll see about the firewall and what I can do about it.
EDIT: Tested with firewall off. Didn't change anything.