When I'm in the web cam chat room, when I type, nothing shows in the box, when I click on enter , my message doesn't go out. I can click on a smilies face, that works. The messages I get from people, I can read. I use Mozilla Firefox. I have cleaned the cookies and cache. I have no trouble typing on a site like this one, just the web cam co.
In Firefox, make sure you've enabled/accepted ActiveX controls for that specific website. A lot of Webcam chat rooms use Flash, make sure your Flash Player is set to allow key strokes.