Broken installation (no such file -- rubygems)?

Hi,

I had a working installation of Rails after following these
instructions:
(Dan Benjamin)

However, now I am getting the following error:

ruby script/server
./script/…/config/boot.rb:15:in require': No such file to load -- rubygems (LoadError) from ./script/../config/boot.rb:15 from script/server:2:in require’
from script/server:2

One thing I did inbetween is de-install fink by deleting /sw, then
re-install it and install a number of packages (basically the ones I
need for running Trac)

Does rails install anything in /sw? Where should rubygems be? What else
could be the source of the problem?

Ingo