It is possible to set permissions and pages up so that no one can log in. If this happens, it's necessary to reset the portal database to defaults. This is a procedure for doing so.
To do this, from a root shell:
then from a root mysql cli:
than back at root shell:
This will wipe out all non-default users and passwords, as well as any custom portal pages, dashboards, etc.
It's a good idea to back up the jbossportal database before customizing dashboards to avoid this problem.