I was unable to connect to the chat through my firewall. That's probably not a big deal, not THAT many people have firewalls...
I notice that the chat is hosted on a different server, do the rooms generally have traffic? If all the traffic in the chat rooms are coming just from your site, you will find that they are empty a LOT of the time.
One good way to get people in is to have a scheduled 'event' where you advertise something nifty happening at a certain time. Those work really well if you find that your rooms are empty a lot of the time. As more and more people use your chats, you will find that they are more and more often full.
This only applies if all the room traffic are people from your site. If they also get traffic from other sites, then disregard. I wasn't able to actually see the room
