amazing all the "technical" knowledge that's abound. : )
www.java.com - make sure you're up to date.
for older machines, typically people love to load the google toolbar, the live toolbar, the "my favorite game" toolbar and a bunch of other crap onto the system and they expect the system to be flawless and work despite the garbage put around it.
if you have java installed - remove *all forms of it* in the control panel (if you have more than 1 version showing there) and install *ONLY* the latest version and try again. if you only have 1 version, do a version check on java.com and make sure it's the latest. if not uninstall, reboot, and reinstall java fresh and see if it works.
add-onchat (the people who make the chatroom software) recentely upgraded and a LOT of their features need the latest java and it can get touchy. a big reason why i'm pulling away from them and going to a flashed based solution for my own use.