It seems that perhaps the java based chat client may not work for all. This could be related to your browser, or other issues.
One alternative if you cannot run the java (internet) based client, is to try downloading a program such as mIRC. There are many IRC based chat programs which you can use to connect to OddChat available for free from sites such as
www.download.com
Instructions for configuring these clients can be found in the OddChat help at
http://www.oddworld.au.com/oddchat/help.htm.
Eventually we would like to get another kind of chat room for OddChat, that is perhaps more user friendly and has more features. But it's a matter of finding a good free (or at least low cost) one that isn't filled with ads.
Abe Babe...