Many thanks to Tony Celini at the recent NJ FM Developer group meeting for this solution.
PROBLEM: Admin Console for FM Server 11 running on Mac OX 10.7.4 (Lion) but not sure which version of Java was running at the time when we had multiple instances of users logged in at the same IP that were now being booted out of the system at logon. We ran a backup and safely closed all the FM hosted files using the Admin Console. Tried to stop the server, but got a "hang" with the Admin Console. Prior to restarting the sever, my IT associate ran a Mac Software Update. When the server rebooted, it was now running with Java version 1.6.0_33. The FM files were all hosted and running, however when trying to launch the Admin Console we got the message "Application Error: Unable to launch the application."
SOLUTION: On a Mac, go the the Utilities folder and launch the application Java Preferences.Select the Network tab and then Click the Delete Files...button. This deletes all the Java Temp files. Also, set the amount of disk space for storing temporary files to around 256 MB. After you close the Java Preferences window to save the changes, then go to your web browser, type in the server's IP address followed by :16000 to bring up the Admin Console start page.
My deep gratitude for this solution and not having to venture into unfamiliar territory with Terminal command lines to manage the server!