IPC + Eclipse

I have a problem to make the communication between two portlets.
I added the jar: vaadin-ipc-for-liferay-1.0.0.jar in the Eclipse project and I’m still with errors.
I added the jar vaadin-ipc-for-liferay-1.0.0 on: … tomcat \ webapps \ ROOT \ WEB-INF \ lib.
I’m doing Liferay >> SDK >> all but the errors appear.

I work with Vaadin 6.8.12 and Liferay 6.2 CE…
Where is the problem?
I have to manually compile the widget set?