After running thousands of devtests I did a sanity check by grepping for SEVERE in the server log. I saw this:
[#|2011-05-18T12:09:43.473-0700|SEVERE|glassfish3.1|javax.enterprise.system.tools.admin.org.glassfish.config.support|_ThreadID=17;_ThreadName=Thread-1;|Exception while adding the new configuration : Constraints for this Cluster configuration have been violated: on property [ name ] violation reason [ Invalid cluster name. The name must start with a letter, number or underscore and may contain only letters, numbers, and these characters: hyphen, period, underscore, and semicolon. ]|#]
What was the name of the cluster? That info must be right at the fingertips of the code that created this message. Why not include it?