Rails JSR286 portlets

Hi,

I created rails application and when i tried to build portlets i was
getting an error .
Please see my steps

srinath@srinath-laptop:~$ rails example
srinath@srinath-laptop:~$ cd example/
srinath@srinath-laptop:~/example$ ls
app db lib public README test vendor
config doc log Rakefile script tmp

srinath@srinath-laptop:~/example$ caterpillar portlets
/usr/local/lib/site_ruby/1.8/rubygems.rb:149:in activate': can't activate activesupport (= 2.0.2, runtime), already activated activesupport-2.3.3 (Gem::Exception) from /usr/local/lib/site_ruby/1.8/rubygems.rb:49:ingem’
from
/home/srinath/.gem/ruby/1.8/gems/caterpillar-1.0.1/lib/caterpillar.rb:50
from
/home/srinath/.gem/ruby/1.8/gems/caterpillar-1.0.1/lib/caterpillar.rb:47:in
each' from /home/srinath/.gem/ruby/1.8/gems/caterpillar-1.0.1/lib/caterpillar.rb:47 from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:ingem_original_require’
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:

I installed caterpillar gem and also have rails 2.3.3, 2.1.2, 2.0.2…

Could any one help me on this …