1.9.1

I tried to instal Ruby 1.9.1 based on the instructions at
hivelogic.com but after completing the process I discovered that the
Ruby.h file was missing (Discovered when I tried to install Rmagick.).
I fired up Textmate and entered puts “Hello” and hit command-R.
Command not found.
Is there something missing from these instructions or is there
something wrong with the code?
Help!!