You can find the full source code for this website in the Seam package in the directory /examples/wiki. It is licensed under the LGPL.
Weld will not create beans if it can't load the class, or some class dependency. You can view these errors by increasing the log level. For example, on JBoss AS, start it with:
./run.sh -Djboss.server.log.threshold=DEBUG
to enable debug logging in server/default/log/server.log.