In the JMX Security section in the installer, where it asks the security domain, admin username, and admin password. The admin password field is not visible and although enterable you cannot see what the value is. Shame on you guys for not using a layout manager. ;)
http://jira.jboss.com/jira/browse/JBINSTALL-59. This is probably a 3rd party issue (IzPack installer). We will try to reproduce this on Ubuntu 6.06.