Hi Gerardo,
How do you get the example code? Did you clone the entire repository from github?
The error inside eclipse is basically saying that you have the jbpm-example project but you don't have the parent project.
Please let us know how do you download that code. You can always try to build it from the console with:
mvn clean install -DskipTests eclipse:eclipse
Notice that eclipse:eclipse will create all the artifacts required by eclipse to work :)