Hello,
you have to set up a data source in jboss-as-xxx/standalone/configuration/standalone.xml. The datasource name must be the same as in jbpm-gwt-console-server.war/WEB-INF/classes/META-INF/persistence.xml. It's recommended to set up a different data source from jbpm-human-task.war as well (due to performance reasons mainly in production mode). See
http://kverlaen.blogspot.cz/2011/07/jbpm5-on-as7-lightning.html
or take a look into jboss documentation how to set up the data sources.
The second problem means that you have to set up a security domain for your jbpm-console. It's described also in the link above. If you have jbpm-installer somewhere, you can see how to do that from its own configuration files.