It wasn't working for me either, but as i later discovered, it's just the homepage that wasn't working. I was able to access the site by going through my history and just jumping to other pages on the site. ie, this one:
http://www.daviscup.com/ties/tie.asp?tie=100005917
I think that is the Canada-Romania tie, which blah, who cares

But I was able to access everything else aside from the homepage from that, so it's all good.
Of course, superpinkone says it's up again. I"m just sharing this incase the homepage dies a horrible death again and this method of getting in to get the scoreboard will still work.
Cheers!