NPE in Chapter09a.java

Hi,

In the org.xith3d.xin.Chapter09a class provided in the xith-tk, when I click, I get the following stack trace :

Code:

Exception in thread "Thread-3" java.lang.NullPointerException
at org.xith3d.render.DefaultRenderer.renderOnceInternal(DefaultRenderer.java:431)
at org.xith3d.render.DefaultRenderer.performPickings(DefaultRenderer.java:522)
at org.xith3d.render.DefaultRenderer.renderOnce(DefaultRenderer.java:563)
at org.xith3d.base.Xith3DEnvironment.render(Xith3DEnvironment.java:445)
at org.xith3d.loop.RenderLoop.renderNextFrame(RenderLoop.java:557)
at org.xith3d.loop.RenderLoop.loopIteration(RenderLoop.java:580)
at org.xith3d.loop.RenderLoop.update(RenderLoop.java:634)
at org.xith3d.loop.UpdatingThread.nextIteration(UpdatingThread.java:172)
at org.xith3d.loop.RenderLoop.loop(RenderLoop.java:692)
at org.xith3d.loop.UpdatingThread.run(UpdatingThread.java:220)
at org.xith3d.loop.RenderLoop.run(RenderLoop.java:715)
at java.lang.Thread.run(Thread.java:619)

which correspond to this line of code :

Code:

if (pickRequest == null)
{
if (root instanceof VirtualUniverse)
universe = (VirtualUniverse)root;
else if (root instanceof Locale)
universe = ((Locale)root).getUniverse();
else if (root instanceof GroupNode)
universe = ((GroupNode)root).getRoot().getLocale().getUniverse();
else
throw( new IllegalArgumentException( "root must be eighter VirtualUniverse, Locale or GroupNode." ) );
}
else
{
universe = ((GroupNode)pickRequest.getGroups().get( 0 )).getRoot().getLocale().getUniverse(); /// << ---- THIS line of code
}

Any ideas ? Does it work for you ?