Searching for chat module

Hello,

I'm looking for a good chat/instant-messenger module for attracting unregistered users to a community. (chat between registered and unregistered users)

- I tried already AjaxIM, Chat Block, PHPfreeChat, PJirc, Userplane but they all give errors / don't seem to work
- I tried Chat room module but I don't like it (too simple)

Does anyone have a good idea/module suggestion?

Thanks,
Greetz,