This issue provided by Jboss classloading specific.
Log messages seems from MyFaces library - but this demo DON'T USE MYFACES, and war contain only Sun RI implementation !
As I thing, You have myfaces libraries loaded by other application or put it in server lib folder.
See http://wiki.jboss.org/wiki/Wiki.jsp?page=ClassLoadingOverview and related pages for properly configuration.
P.S. This sample run without problem on clean Jboss 4.04.GA installation.