Primefaces withEclipse Helios, JSF 2.0 and jBoss 6 ClassNotFoundException thrown when deploying

I'm working on a web application (EAR) project using eclipse IDE Helios, jBoss 6 AS, JSF 2.0, when i installed the PrimeFaces library my projects cannot be deployed again and a ClassNotFoundException thrown. I installed the PrimeFaces library by referencing the .jar (located in the WEB-INF/lib) in the web library, after some searchs on google i modified the web.xml according to this topic

But the 开发者_开发技巧same problem appears, the PrimeFaces users guide is not free and i'm blocked at this problem. Thanx ...