Hello,
I had the same problem using Ubuntu 9.04 _Jaunty Jackalope_ - Release i386 (20090420.1)
I solved it moving the rails version (2.1.0) "frozen" in: /usr/share/rails
to an other folder (/usr/share/rails_bak) and copying rails version 2.2.2 in /usr/share/rails.
I hope that it can help you, See you,
