zlib error when using rbenv across ctovm instances

gistfile1.txt

https://github.com/sstephenson/ruby-build/wiki

I had rbenv installed in my global home dir, but got this error when trying to install a gem:
-bash-4.1$ gem install httparty
ERROR:  Loading command: install (LoadError)
    cannot load such file -- zlib
ERROR:  While executing gem ... (NameError)
    uninitialized constant Gem::Commands::InstallCommand

# Installed zlib-devel
-bash-4.1$ /project/admin/bin/sudo yum install zlib-devel

# Reinstalled ruby
-bash-4.1$ rbenv install 1.9.3-p194