I ran into one of those brickwalls when I tried to run our latest-and-greatest web app. It had just switched from JRuby (slow as a dog for development) to Ruby (smooth as a baby's bottom), everything seemed fine, Ruby 1.9.3(-p327) installed, bundle did it's magic, rails s .......
.rvm/gems/ruby-1.9.3-p327/gems/sqlite3-1.3.6/lib/sqlite3/sqlite3_native.bundle: [BUG] Segmentation fault
A hunt around the Interwebs hinted that a little something might get you going:
gem install heroku
Weiiiiiiird but worked (for me). I've no clue why it might help, nor do I have the brainpower this morning to work out why exactly, so your mileage may vary, but it's worth a go if it gets you on the path to Ruby enlightenment.