I can't connect to a web site via the site's own WiFi.

This is a strange one. When I'm in the New York Public Library and connected to the internet via their WiFi I can connect to any web site EXCEPT the New York Public Library's! (www.nypl.org) It tries connecting then times out every time. I can connect to the NYPL's site when I'm not there from home or other WiFis public or private, and when there I can connect to it on my iPhone, but not from my computer with either Firefox or Safari. Other people with Macs can access the site from there and I went over my settings with one of them but could find no differences.

I'm using 10.5.7 and have the latest updates for Firefox and Safari and the latest updates for OSX. What's frustrating is that when I'm at the library doing research there are databases one can only access from there, not from outside, so it's a very odd situation. Using iPhone for such a reason is quite impractical, too so I'd appreciate any help anyone can offer. I'm sure it's a setting somewhere in my network prefs or something but I'm baffled as to what it might be - has anyone else ever run across something similar?

Thank you!