rails _x.x.x_ <appname> doesn't work on ubuntu

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,