OK here's a new twist. I recently had to download the new version of the Java applet in order to do business on sharpdots.com. The "iRV2 Chat Room" needs to use the Java applet.
I had to re-install Java when I was having problems. The current version is: 2V1.4.2_05
Click on the graphic.
Click on "Begin Download"
Go to the "Green" block in the upper right hand side of the page and download the current version of the Java applet and allow the applet to install. Most often when you click on the link the install will proceed automatically.
Try the chat room again. I'm using the current version of the Java applet and MS Windows XP SP2. So far so good.
One other issue that I have found is that when pop-up blockers are used, they do not allow the chat window to "pop-up". To resolve this you have to allow pop-up from both the "iRV2.com" and the "http://irv2.infopop.cc/groupee" domain.