JOptionPane.showConfirmDialog hangs in native method sun.awt.UNIXToolkit.readGTKIconData

An external user (###@###.###) has filed an issue against NetBeans Installer (which runs on Java).

The issue is that JOptionPane.showConfirmDialog hangs, the dump shows that it occurs in sun.awt.UNIXToolkit.readGTKIconData native method (GTKLookAndFeel is used).
http://www.netbeans.org/nonav/issues/showattachment.cgi/67433/console.txt
As the result, the main JFrame also hangs.

Bryan has Debian box with 2.6.26 kernel running on amd64 hardware.
(I don`t have Debian at the moment and I could not reproduce it on any other Linux system I have).
He says that Java (32-bit) is installed from Debian repositories and it is ia32-java-1.5.0-sun-1.5.0.16.

Some more info at the issues :
http://www.netbeans.org/issues/show_bug.cgi?id=143775
http://www.netbeans.org/issues/show_bug.cgi?id=143949

Please advise to identify and workaround the problem.

Thanks,
Dmitry Lipin
NetBeans Installer Team Lead
See the dump:
http://www.netbeans.org/nonav/issues/showattachment.cgi/67433/console.txt
I see that JOptionPane.showConfirmDialog is running in EDT, isn`t it?

The problem is that I can`t reproduce it either. This code always works fine and have never caused troubles. That`s why I`m asking for you help : maybe there any some means to identify the part in readGTKIconData which is hanging?

I`ll try to make a simple test case which works for me and doesn`t work on Bryan system.