Installed Latest version of Eclipse and all add-on but can't view app in Chrome browser

[dt_da]

Hello,

I went through the getting started section in the Google App Engine for Java. I installed the following software:

• Eclipse EE IDE (Version: Juno Release Build id: 20120614-1722), 
• plugin GWT SDK 2.4.0 
• plugin eclipse 4.2
• plugin GAE Java SDK 1.7.2.1
• plugin GWT designer 2.6.0 
• Oracle Java SE 7u9 
• Chome extension GWT Developer Plugin 1.0.1133

I tried creating a hello world google web application that uses both GWT and GAE SDKs, but when I try and run it in debug mode it creates a URL which when I click on it gives the following error message:

 If I try creating a hello world google web application with only GAE SDK it does not seem to work at all. 

I followed the instructions here: https://developers.google.com/appengine/docs/java/gettingstarted/

but there weren't very clear on the versions of eclipse to download and use or the version of Java to download and use. Does anybody else have the same issues or can you tell me what I am doing wrong??