Several possibilities.
On your end: your computer may be too slow/old, you may have too many programs running in the background, your computer may not be optimized for broadband, your internet connection may not be fast enough, your computer may not be hooked up to your modem in the fastest way possible.
On their end: there may be too many people trying to watch the feed at the same time, their computers may be too slow to encode the video in realtime, their internet connection may not be fast enough to the distribution servers.
In between: the internet backbone between you and your target may not be reliable, the distance may be too great for streaming video, one or more nodes in between may be experiencing hardware or software issues.
What can you do?
If you don't have broadband, don't bother. If you get your broadband through a satellite system like DirectTV, don't expect great things; the lag from earth to GSO to earth will kill you on live events. If you are located many miles from your ISP, you may have issues due to line length. If you are using a cheap computer you bought more than five years ago(or an expensive computer you bought more than eight), you may have speed issues.
If you think you're okay with the above, do these things:
Go to
www.windowsupdate.com , select the custom option and install just about everything under all three categories. The only thing I don't install is Search 4.0 for XP.
Go to your computer's manufacturer's website and install any updates for your hardware(especially motherboard and network updates).
If you are using Firefox instead of IE, make sure to update it to the latest version(3.0.3).
Go to
www.speedtest.net and find out your internet connection speed.
Go to
www.speedguide.net and install the TCP/IP Optimizer(shortcuts section, halfway down the left side). Use the numbers from the speed test to position the slider.
Shut down any uneccissary programs, including almost everything in the system tray(lower right corner next to the clock). When I'm watching a live event, the only thing showing is the volume control. If you're feeling adventurous, press ctrl-alt-delete, select the processes tab, and shut down everything you can. Don't stop explorer.exe, svchost.exe, lsass.exe, services.exe, or winlogon.exe. There are a few others that you can't shut down, but Windows won't let you anyway. I can get my machine down to 14 active processes in my barebones mode.
Make sure the connection between your modem and computer is fast enough. If you have the option, connect the two using 10/100 Ethernet. If you must use USB to connect them, try to make sure both are USB 2.0.
Any other techies want to add or contradict? I'm off to get food before kickoff.