Using Java chat on a Sun?

So I just tried accessing chat from the lab (which I probably shouldn't be doing anyways) and it gave the null connect error. This seems rather odd, as Sun owns Java and I highly doubt our version of Java is outdated, as we use a Java intensive equipment management system. Are there any other reasons why this error could occur?

There's a corporate firewall blocking you connected to port 6669 outside your LAN where FFChat is running :p Or a local firewall, both can cause that error too.