The Vaadin Composer don't run

Hi all.
I’m new of Vaadin.
I’ve installed the Eclipse Plugin as in the Vaadin book. I can compile the sample project and it run well (local server tomcat).
But i cannot run the vaadin composer.
When i open a new item with Vaadin Composer, it give me a blank tab that don’t do nothing.
Following some notes on internet I’ve installed also the AFT package that should contain the XULrunner, but nothing.
what i have to do?