Hi Luis Victor,
is this your problem: Cannot see any task for john or mary?
The default JBPM5.3 full installer should works without problem when we follow the user guide here http://docs.jboss.org/jbpm/v5.3/userguide/ch.installer.html
this screencast may help you too http://people.redhat.com/kverlaen/jbpm-installer-console.5.2.swf
please let us know what is the problem that you get after following the screencast.
Regards,
Thomas Setiabudi