For Instant Messaging, the Java Enterprise System installer uses /opt/SUNWiim on Solaris as the default installation directory (im-svr-base). However, if you are using a shared disk for configuration files and binaries, you must specify a global (shared) installation directory. For example: /global/im/opt/SUNWiim.
If you are using a local disk, you can install Instant Messaging to the default directory. However, you should Install Instant Messaging in the same directory on each machine in the node.