After the very first installation of wildfly 8 beta1 the image http://localhost:9990/error/linux_add.PNG gets displayed. But it is not the complete truth:
Here my console

#> /tmp/JBossAS/wildfly-8.0.0.Beta1/bin$ ./add-user.sh

What type of user do you wish to add?
a) Management User (mgmt-users.properties)
b) Application User (application-users.properties)
(a): a

Enter the details of the new user to add.
Using realm 'ManagementRealm' as discovered from the existing property files.
Username : myadmin
Password requirements are listed below. To modify these restrictions edit the add-user.properties configuration file.
JBAS152565: Password must not be equal to 'root', this value is restricted.
JBAS152565: Password must not be equal to 'admin', this value is restricted.
JBAS152565: Password must not be equal to 'administrator', this value is restricted.
JBAS015269: Password must have at least 8 characters!
JBAS015268: Password must have at least 1 alphanumeric character.
JBAS015266: Password must have at least 1 digit.
JBAS015267: Password must have at least 1 non-alphanumeric symbol.
JBAS152565: Password must not be equal to 'myadmin', this value is restricted.
Password :
Re-enter Password :
What groups do you want this user to belong to? (Please enter a comma separated list, or leave blank for none)[ ]:
About to add user 'myadmin' for realm 'ManagementRealm'
Is this correct yes/no? yes
Added user 'myadmin' to file '/tmp/wildfly-8.0.0.Beta1/standalone/configuration/mgmt-users.properties'
Added user 'myadmin' to file '/tmp/wildfly-8.0.0.Beta1/domain/configuration/mgmt-users.properties'
Added user 'myadmin' with groups to file '/tmp/wildfly-8.0.0.Beta1/standalone/configuration/mgmt-groups.properties'
Added user 'myadmin' with groups to file '/tmp/wildfly-8.0.0.Beta1/domain/configuration/mgmt-groups.properties'
Is this new user going to be used for one AS process to connect to another AS process?
e.g. for a slave host controller connecting to the master or for a Remoting connection for server to server EJB calls.
yes/no? yes
To represent the user add the following to the server-identities definition <secret value="abcdefgh" />

So the image should be replaced to avoid confusion on new Wildfly users.