I've had to change the chatbox to a simpler version as the other one was still crashing the forum for some people. This one only works on the main forum page, which is fine for generic chat.

However I've found a new plugin, but as it will cost $65 I'll ask if people think it'll be useful.

http://www.arrowchat.com/index.php?do=screenshots

This works exactly the same way as the chat on Facebook, and along with the above chatbox does not add as much bandwidth to the forum as the old scripts.