Been trying to install this on CentOS 5.7 and 6 but with no luck. So tried installing it on Ubuntu and was able to install and configure it with no errors. Here are the steps on installing Ruby/REE using RVM, ROR and Passenger with Apache on Ubuntu (10.04 and 11.10).
On a fresh Ubuntu (version 10.04 or 11.10) install RVM system requirements:
$ apt-get install curl git