Help!! Over the past few days, I am no longer to see all of the conversations taking place in a chat room when I am there

At the most, I can see maybe 4 people typing in a very busy room. Although I initially thought the rooms were just quiet, I now know that there is a problem with my ability to see the typing. Friends are PMing asking why I didn't say hello to them in the room and several have verified that conversations are taking place that are not showing up on the chat window.
The problem began earlier this week out of nowhere. I've reloaded YIM twice to see if that would fix the problem and no effect. Have tried with my firewall on and off and no difference. Entered YIM through the taskbar icon and through the icon on my browser and no difference. Connection setting is set at "no proxies" and filters are set at none.
Any help would be appreciated!! Makes being in a chat room a very boring experience
