Can't find rails after re-installing/upgrading Kubuntu

Hello Railers (?),

I have just re-installed my machine with the lattest Kubuntu, which brings with Rails 1.2.4 instead of 1.2.3. Now my Rail project doesn't start anymore. At first I've got this message:

Cannot find gem for Rails ~>1.2.3.0:
    Install the missing gem with 'gem install -v=1.2.3 rails', or
    change environment.rb to define RAILS_GEM_VERSION with your desired version.

then I went and I updated environment.rb and now it says:

Cannot find gem for Rails ~>1.2.4.0:
    Install the missing gem with 'gem install -v=1.2.4 rails', or
    change environment.rb to define RAILS_GEM_VERSION with your desired version.

Just to check I created a new rails project and it just works. Any ideas what else I am forgetting to change/update to have my old project working?

Thank you.

What does it environment.rb say in the project that works?

Hello,

What dependencies?

Hello,

Just for the record, I kind of solved it. I used a program called meld to make
a recursive comparition and aside minor differences in boot.rb, I've noticed
than now, the new projects, contain a copy of rails while the old didn't.
I've just made the copy and it worked.