Error in Java VNC client

So I tried to use the Java VNC client available here. And before you ask, I do have VNC set up correctly on the server computer. The problem is, once I enter the correct password (only happens if I enter it correctly) a big blank window opens up and closes immediately (I was able to capture it by timing a screen cap just right)

and then I just get this error message:


Any idea what's going on? Basically I'd just like to get this or some other Java VNC client working so I can access my computer even when I'm on someone else's who doesn't have a VNC client.

 

Chicken of the VNC is an app that needs to be downloaded and run. And, as I said