Installation problem

Hi,

I am trying to install Ruby gems on SUSE Linux 10.0, while executing the
command “sudo gem install rails” I am getting a error

/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in
require__': no such file to load -- zlib (LoadError) from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in require’
from /usr/lib/ruby/site_ruby/1.8/rubygems/package.rb:9
from
/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in require__' from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in require’
from /usr/lib/ruby/site_ruby/1.8/rubygems/builder.rb:1
from
/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in require__' from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in require’
from /usr/lib/ruby/site_ruby/1.8/rubygems.rb:61:in `manage_gems’
from /usr/bin/gem:4

However I have followed the procedure which is given on
http://developer.novell.com/wiki/index.php/Configuring_Ruby_Rails_for_Apache_on_SUSE_Linux_Enterprise_Server#Configuring_Ruby_Rails_for_Apache_on_SUSE_Linux_Enterprise_Server

Can anyone please help me on this.
Thanks in advance.
Regards,
Dev