Have you tried a different browser? Some things work with some browsers but not others. Another thing to consider is browser add-ons, like the ones for Firefox. Some add-ons cause weird conflicts. If you are using Firefox and recently put on any new add-ons try temporarily disabling them. Does the chat here use java? If so it might be that you need a java update.
Perhaps someone will come along with more specific answers, but that's all I can think of currently. Not sure how the chat function works here at Chaz, but I have never tried it. Just not much of a fan of chatrooms any where, prefer forums.