Does your app run in jetty?
When you call mvn gwt:run - does everything work as expected? Or is there an error in the gwt console?
I was failing with mvn gwt:run too, but that was where I saw the real problems. I eventaully did "organize imports" on the project node from package Explorer and recompiled, and I was on my way to fixing the errors.
The app is up now, running in OpenShift here www.smup-app.com. We should launch in another month.