tomcat-instance-manager.bash installed with the currently stable tomcat-7.0.32 has a broken --group option. It uses "id --group <groupname>" to determine if the group is valid, but this restricts the set of groups that can be used to effectively those that the root user is a member of.
Created attachment 378796 [details, diff] Patch for tomcat-instance-manager Proposal to fix tomcat-instance-manager. Note: I've also replace id --user with getent.
@java: Any comments on this?
Fixed in tomcat-6.0.41 and tomcat-7.0.56