On Sep 2, 6:49    ꮮ 
> Hello,
>  §       > Ubuntu, but recently i've changed my Ubuntu version, then i installed
> rubygems version 0.9.4-4, but when i try to install this gems i'm
> getting this error:
>
> =====================================
> ubuntu@eeepc:~$ sudo gem install zlib
> /usr/bin/gem:10: undefined method `manage_gems' for Gem:Module
> (NoMethodError)
> ubuntu@eeepc:~$
> =====================================
>
> What is wrong?

- There is no gem "zlib"
- Ubuntu had patched and modified RubyGems to install gems using their
layout, you have two options:

A) Update Ubuntu RubyGems package
B) Uninstall it and manually install RubyGems on top.

Ask the uncle google about this, there are several users with similar
issues and their own solutions.

- manage_gem has been deprecated several versions ago, the issue you
see means somehow you "gem" script has become stalled or other issues
due some upgrade.

HTH,
--
Luis Lavena