I've been trying to set up Ruby on Rails for Ubuntu 11.10 following these instructions, but I can't get it to work.

I'll follow the install guide all the way up to "rvm install ruby-1.9.2", and at that point terminal will configure ruby-1.9.2, compile it, and as it starts installing it my computer will shut down. Not freeze up or become unresponsive, but totally shut down.

What might be causing this error, and how might I fix it? Thanks!