Make sure that wget is installed
Remove hardcoded 'ec2-user' home directory and just use whatever's there.
Make sure GRAILS_HOME and PATH are set even if grails is not downloaded by the script.
Pass JAVA_OPTS to the grails command to enable it to use a proxy
Reuse the HOME_DIR variable for creating the processor and reader paths
Make the script install/build ice in the directory it is run from to avoid ending up with an extra copy under the home directory.