Install LoadUI on Ubuntu 12.04 in GUI mode

Downloaded LoadUI-2.6.8.sh

running sh LoadUI-2.6.8.sh gives

java.lang.NoClassDefFoundError: java.awt.Container
at com.install4-j.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)
Could not display the GUI. This application needs access to an X Server.

What all other dependencies do i require to install LoadUI in GUI mode.

System - Ubuntu 12.04 LTS
JAVA version - java version "1.6.0_30"
OpenJDK Runtime Environment (IcedTea6 1.13.1) (6b30-1.13.1-1ubuntu2~0.12.04.1)
OpenJDK 64-Bit Server VM (build 23.25-b01, mixed mode)

install4j version - 5.1.11