[web] gwt question

i've started to play with GWT recently; i've made a simple test program: import com.google.gwt.core.client.EntryPoint; import com.google.gwt.user.client.Window; public class Main implements EntryPoint { public Main() { } public void onModuleLoad() { Window.alert("hello world"); } } while this runs ok locally, and the dialog box appears, when i put the generated files (from the build/www folder) on my googlepages, nothing happens; the &#106avascript console shows no errors. any idea what's wrong? thanks for any help.