I know Ustream is the most common for the streamers bringing you pool and as of late there has been trouble. Here is what I found to fix the latest problem. You need to go in Command Prompt, just type it in the search box of your computer. When your in there copy and paste this ipconfig /flushdns and it will flush the dns. Then you restart your computer and go to Ustream.tv and see if your able to access the site and streams. Should work okay as it did for me.