I am trying to learn Ruby on Rails from the Sitepoint book Simply Rails 2. I have downloaded the InstantRails installation file and followed the instructions in the book. however when I try to run the update command:

gem update --system

I get the error HTTP Response 302 fetching http//gems.rubyforge.org/yaml

I cannot see what I have done wrong, please can anybody help and explain what I need to do? I am a newbie to Ruby and using the command line interface. Many thanks