I just came across this topic. If you are still having an issue, verify your channel name. I've noticed that USTREAM doesn't necessarily use your Channel Name in USTREAM as the Chat Channel Name on the network. ie: My channel might be called "Channel" on ustream.tv but on the chat network it will be "Channel123" The easiest way to check this is to logon to the USTREAM Chat Network with mIRC and do a /whois on someone you know who is on the channel when connected via the website. It should show the actual channel name they are connected to. Then just /join that channel and you should see everyone.
