I don't know how your chatroom works or what its problem is, since I can't see the link. But if you're having browser problems with it, I'd suggest switching to another one that's more flexible. Try using Chatwing chat app. You only nee to copy the supplied code to your site for it to be usable. You can visit the site for more info. Chatwing.com
follow these steps :
1.) In the Firefox drop down menu (the top left of your browser window), chose "Ad-ons"
2.) Make sure you're on the "Extenstions" tab (tabs on left hand side)
3.) Click on "Options" next to Ad-Block Plus
4.) Click on "Filters" at the top
5.) Click "Update all Subscriptions" and then click "okay"
your chat will work now properly.