Your firewall and/or router will need to allow unrestricted communications on ports 80, 1119, and 6881 - 6999.

By my calculations, about 96 percent of all computer repairs are done, not by the local computer guy or the Geek Squad, but by The Friend Who is Good With Computers. Often that friend is nothing more than an average computer user who knows how to look up error messages on Google, but it doesn't matter -- once they become known as TFWIGWC, they will get the call every time something goes wrong. And they will fix it, probably for free, because TFWIGWC pities you.