Help com Loja virtual

Eu estou gostando muito das aulas de Ecommerce mas estou com alguns problemas Aula-17:

WARNING: multiple versions of ant detected in path for junit jar:file:/C:/Program%20Files/NetBeans%206.9.1/java/ant/lib/ant.jar!/org/apache/tools/ant/Project.class
and jar:file:/C:/Program%20Files/glassfish-3.0.1/glassfish/modules/ant.jar!/org/apache/tools/ant/Project.class
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GRAVE: Exception while deploying the app
java.lang.IllegalArgumentException: Invalid ejb jar [EcommerceDevmedia.jar]: it contains zero ejb.
Note:
1. A valid ejb jar requires at least one session, entity (1.x/2.x style), or message-driven bean.
2. EJB3+ entity beans (@Entity) are POJOs and please package them as library jar.
3. If the jar file contains valid EJBs which are annotated with EJB component level annotations (@Stateless, @Stateful, @MessageDriven, @Singleton), please check server.log to see whether the annotations were processed properly.
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GRAVE: ejb.embedded.exception_instantiating
javax.ejb.EJBException: Failed to deploy EJB modules - see log for details
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Esses são os erros mais graves ate o momento, o que deve ser e como devo resolver esse problema? Já resolvi os problemas coma aula -18, mas ainda dá problemas.
Por favor alguém me ajude, Obrigado.