A instalação do Visual Paradigm for UML fornece: java.lang.NoClassDefFoundError: java.awt.Container

Question

Eu baixei recentemente o Visual Paradigm for UML para o meu sistema (Ubuntu 12.0.4 LTS).

Quando tentei instalá-lo, ele falhou. Aqui está o stacktrace:

Unpacking JRE ...
Preparing JRE ...
Starting Installer ...
java.lang.NoClassDefFoundError: java.awt.Container
    at com.install4j.runtime.installer.frontend.headless.AbstractHeadlessScreenExecutor.init(Unknown Source)
    at com.install4j.runtime.installer.frontend.headless.ConsoleScreenExecutor.<init>(Unknown Source)
    at com.install4j.runtime.installer.frontend.headless.InstallerConsoleScreenExecutor.<init>(Unknown Source)
    at com.install4j.runtime.installer.Installer.getScreenExecutor(Unknown Source)
    at com.install4j.runtime.installer.Installer.runInProcess(Unknown Source)
    at com.install4j.runtime.installer.Installer.main(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.exe4j.runtime.LauncherEngine.launch(Unknown Source)
    at com.install4j.runtime.launcher.Launcher.main(Unknown Source)
java.lang.NoClassDefFoundError: java.awt.Component
    at javax.swing.ImageIcon.<clinit>(Unknown Source)
    at com.install4j.runtime.installer.frontend.GUIHelper.loadIcon(Unknown Source)
    at com.install4j.runtime.installer.frontend.GUIHelper.<clinit>(Unknown Source)
    at com.install4j.runtime.installer.helper.InstallerUtil.reportException(Unknown Source)
    at com.install4j.runtime.installer.Installer.main(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.exe4j.runtime.LauncherEngine.launch(Unknown Source)
    at com.install4j.runtime.launcher.Launcher.main(Unknown Source)

Parece que o instalador não consegue encontrar uma classe na biblioteca do WT. Eu não consigo ver como isso pode ser possível. Alguém sabe o que está causando isso e como posso corrigi-lo?

[Atualização]

java version "1.6.0_24"
OpenJDK Runtime Environment (IcedTea6 1.11.5) (6b24-1.11.5-0ubuntu1~12.04.1)
OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)