Has anyone succeeded to start glossitope on Linux GNOME with Sun's JDK?

Site : http://www.glossitope.org
URL : http://www.glossitope.org/downloads/daily/Glossitope_buffered.jnlp

I'm trying it on Ubuntu 7.04 and Fedora Core 6 GNOME but it always fails.

        at com.sun.java.swing.plaf.gtk.GTKLookAndFeel.initSystemColorDefaults(GTKLookAndFeel.java:1267)
        at com.sun.java.swing.plaf.gtk.GTKLookAndFeel.loadStyles(GTKLookAndFeel.java:1509)
        at com.sun.java.swing.plaf.gtk.GTKLookAndFeel.access$000(GTKLookAndFeel.java:37)
        at com.sun.java.swing.plaf.gtk.GTKLookAndFeel$WeakPCL$1.run(GTKLookAndFeel.java:1449)

(full stack will be attached into attachment field)

Changing locale to C does not help. Very simlier NPE happens in some bug
reports (6389282) so I tried the latest JDK7 but it also does not help.
When I switched Desktop from GNOME to KDE, it works fine. Any GTK L&F
problem is still happening?