iChat problems

ever since i got my new macbook pro, i have been using iChat for both video and text chat. Lately though, I am no longer able to join multiple video conferences with my friends. It's odd because it has worked perfectly for me up until about a week ago. Im using the same internet connection that I have been using the whole time and am confused as to what has happened. Can someone help me? I can be invited to a single video chat, but not a multiple. It says I;m in another conference when I know that I'm not. PLEASE HELP

thanks

Something obviously changed between then and now. Did you install any updates? New software? Added any new USB peripherals? How about your chat buddies? Did they change anything on their end?