[Users] upgrade to jboss-as-7.1.1.Final reports "Faild to load db driver".

I upgraded from jboss-as-7.1.0.Beta1b to jboss-as-7.1.1.Final on two machines (from zip), both running rhel6.2. On the first it went smooth, but on the second machine, I am unable to get engine started. When I run "engine-config -l" I get error - "Faild to load db driver.". Noticed that postgresql-jdbc.jar does not exist under /usr/share/jboss-as-7.1.1.Final. It still exists under /usr/share/jboss-as-7.1.0.Beta1b/modules/org/postgresql/main/. Which step did I miss? Regards, Sharad Mishra IBM