Please see :
http://blogs.sun.com/swchan/entry/jdbcrealm_in_glassfish
actually the db-user is not a mandatory property. The table in the blog indicates that the default value is picked up from connection pool configuration. So can you check that.
Also did you explore what Jagadish has suggested above that somehow "jdbc/komodo_G3" is getting overwritten in the JNDI with a Hibernate SessionFactoryImpl after the first login or something like that is happening.
So change your jdbc-resource name : <property name="datasource-jndi" value="jdbc/komodo_G3"/> to be something else.
[Message sent by forum member 'kumarjayanti' (kumarjayanti)]
http://forums.java.net/jive/thread.jspa?messageID=253946