gwt problem

[kyuzo]

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 javascript console shows no errors. any idea what's wrong?
thanks for any help.