I've download eclipse-jee-galileo-win32.zip and following instruction of this post, http://blog.kukiel.net/2009/09/coldfusion-on-google-app-engine-with.html
After that, I encounter following errors once I've deleted war file and replace openbd's war files into my project.
alt text http://img411.imageshack.us/img411/3479/52229590.png
Please let me know if you have such problem just like me.
Make sure that you are running the latest SDKs (Google Web Toolkit and Google App Engine). I had this same issue until I switched to the latest versions when I first started out as well.
You can see which ones you are using for a particular app by opening up its properties and looking under Google. The latest versions are 1.3.5 (App Engine) and 2.0.4 (Web Toolkit). If you are on older versions look for updates, new features to install the latest.