Comment by tamplinjohn: You should have a ?gwt.hosted=... portion of the URL -- otherwise the plugin isn't being loaded in your browser (and requires you to have compiled your app to JS).
For more information: http://code.google.com/p/google-web-toolkit/wiki/UsingOOPHM --~--~---------~--~----~------------~-------~--~----~ http://groups.google.com/group/Google-Web-Toolkit-Contributors -~----------~----~----~----~------~----~------~--~---
