Logstash 2.3.4 not starting up due to uninitialized constant Gem


I was trying to upgrade to logstassh 2.3.4 but after installing the tar.gz file from the website, when I try to start logstash , I am geting a uninitialized constant Gem error. Can someone please help?

bin/logstash -V

NameError: uninitialized constant Gem const_missing at org/jruby/RubyModule.java:2745 patch! at /local/0/deploy/nypntsrv/logstash/logstash-2.3.4/lib/bootstrap/rubygems.rb:19 setup! at /local/0/deploy/nypntsrv/logstash/logstash-2.3.4/lib/bootstrap/bundler.rb:47 (root) at /local/0/deploy/nypntsrv/logstash/logstash-stage-varys/lib/bootstrap/environment.rb:65

I am trying to run logstash on this environment configuration
OS: RHEL 5.11
Gem: 2.4.5
Ruby: ruby 2.2.2p95

What's your config look like?
Why not use the rpm?