There is now a Ruby 1.9.1 Windows installer available (RC1). Revised the instructions to start from Ruby 1.9.1 and use the Hobo 1.0 release candidate 2 (0.9.103).
Things are looking good!
Rapid_Rails_with_Hobo_Beta_Version_0.9.20
PDF Version:
Rapid_Rails_with_Hobo_Beta_Version_0.9.20
PDF Compressed:
Rapid_Rails_with_Hobo_Beta_Version_0.9.20_smail
