LiveATC applet hangs in firefox3

[Yuri]

I use libjavaplugin_oji.so from jdk-1.6.0.3p4_11 as a Java plugin for 
firefox-3.5.2,1:
~/.mozilla/plugins/libjavaplugin_oji.so -> 
/usr/local/jdk1.6.0/jre/plugin/i386/ns7/libjavaplugin_oji.so
Many applets work fine but this one: 
http://www.liveatc.net/jlgui/jlisten.php?m=klas hangs firefox.

It works ok in windows version of firefox under wine though.

What might be the problem?

Yuri