Enterprise Server v3 Prelude does not include a full EJB 3.0 implementation and does not support traditional EJB modules. Applications can be packaged for deployment in web archive (WAR) format only. You can download a partial implementation of a few EJB 3.1 features using Update Tool, but the bulk of EJB 3.0 (ejb-jar and .ear support) is not available . If you need a full Java EE 5 implementation, Sun Java System Application Server 9.1 (GlassFish v2) is a better choice for now. Web applications are the only Java EE application type supported by Enterprise Server v3 Prelude.
For related information, see the following:
Forum threads: http://forums.java.net/jive/thread.jspa?messageID=301326 and http://forums.java.net/jive/thread.jspa?messageID=318879
Blog post: “EJB 3.1 in GlassFish v3 Prelude” (http://blogs.sun.com/kensaks/entry/ejb_3_1_in_glassfish)
Blog post: “Deployment in GlassFish v3 Prelude” (http://blogs.sun.com/quinn/entry/deployment_in_glassfish_v3_prelude)
Documentation: Chapter 3, Extending Enterprise Server, in Sun GlassFish Enterprise Server v3 Prelude Administration Guide