Gem install problem

(For some reason, by second installment of this problem arrived at the list, but not this - the first part  of it, so here's another attempt.)

I'm rather new to Kubuntu Linux (ver. 7.10) and still getting my sea legs. I knew something's not right with my gem install, so I did the following, from a console

:/$ sudo apt-get purge rubygems
:/$ sudo apt-get install rugygems

which produced this

:/$ Unpacking rubygems (from .../rubygems_0.9.4-1ubuntu1_all.deb) ...
:/$ Setting up rubygems (0.9.4-1ubuntu1) ...

to test the install, I then issued...
:/$ gem help

and got
:/$ /usr/bin/gem:23: uninitialized constant Gem::GemRunner (NameError)         
recalling that I've been able to get to 'gem help' from irb, previously, I try that, from "/usr/bin". I got:

Gem::LoadError: Could not find RubyGem  (>= 0)
from /usr/local/lib/site_ruby/1.8/rubygems.rb:379:in `report_activate_error'
from /usr/local/lib/site_ruby/1.8/rubygems.rb:311:in `activate'
from /usr/local/lib/site_ruby/1.8/rubygems.rb:65:in `active_gem_with_options'
from /usr/local/lib/site_ruby/1.8/rubygems.rb:50:in `gem'
from (irb):1

I really have no idea what all this means or how to respond. I'm guessing (wildly) that somehow rubygems isn't where it's supposed to be, but don't know why, or even where that might be.

Would appreciate any and all help.