I am new to Vaadin and I am trying to do some Tests with this technology.
I Set up my project as a Maven Project under Eclipse with a Tomcat 7 Server.

At first I started with Vaadin 7.0.0 and everything works fine. Now I change the Version from 7.0.0 to 7.1.0 because I like to test the push functionality.
With Vaadin 7.0.0 everything works fine, but since I changed the Version I get the error: 

```
Requested resource [/VAADIN/widgetsets/com.vaadin.DefaultWidgetSet   /com.vaadin.DefaultWidgetSet.nocache.js] not found from filesystem or through class loader. Add widgetset and/or theme JAR to your classpath or add files to WebContent/VAADIN folder.

```

I've read that the DefaultWidget is created by Vaadin but how can I do that?