The CUE GUI only allows one admin user to make changes at one time. So (currently) it allows only one user with admin privileges to be logged in at a time. What may happen is that if you were logged in and then close the browser window instead of clicking the logout button it will keep the user session until the timeout (I can't remember exactly--something like 10 minutes, I believe) upon which you can log in again and get admin privileges.
Unfortunately there is not, but keep in mind that you'll only get that message if there's a different user (with admin privileges) logging into the system. If it were the same, then it would log the original owner out completely and the latest person logging in would have the session.
You can do some monitoring if you do a "trace webInterface session all" command from the CLI. Then you can issue the command:
show trace buffer long | include "webInterface session"
You'll see stuff like:
742 07/10 11:03:29.047 webInterface session "Logged in" Login Failed for marschne : javax.naming.AuthenticationException: netscape.ldap.LDAPException: error result (48)
895 07/10 11:10:00.104 webInterface session "Logged in" Logging in as Administrator
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.