Step Three
Log off then log in to force the reload of the file.
Make a simple check:
luca@ubuntu:~$ env | grep CATALINA_HOME
CATALINA_HOME=/usr/share/tomcat6
luca@ubuntu:~$ env | grep JAVA_HOME
JAVA_HOME=/usr/lib/jvm/java-6-sun-1.6.0.20
CLASSPATH=.:$JAVA_HOME/lib