if tried require 'iphoto2' which depends on the same plist, no more success.

however doing a test with htmltools gives about the same reult from Terminal than TextMate :

the script :

#!/usr/bin/env ruby

require 'htmltools' # <== Line 3

result from TextMate :

result from Terminal :

> ruby essai_htmltools.rb

/opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require': no such file to load -- htmltools (LoadError)

        from /opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in `require'

        from essai_htmltools.rb:3

my gems rep :

> ls -al $GEM_HOME/gems/                                                                         

total 0

drwxr-xr-x   15 root  admin  510 Jul 14 11:05 .

drwxr-xr-x    7 root  admin  238 Mar  8 08:48 ..

drwxr-xr-x    9 root  admin  306 Mar 23 06:46 builder-2.0.0

drwxr-xr-x    6 root  admin  204 Mar 17 08:41 coderay-0.5.0.121

drwxr-xr-x    7 root  admin  238 Mar 23 20:47 htmltools-1.09

drwxr-xr-x    4 root  admin  136 Jul 14 11:05 iphoto2-1.0.1

drwxr-xr-x    9 root  admin  306 Mar  8 08:51 libxml-ruby-0.3.6

drwxr-xr-x    4 root  admin  136 Mar  9 13:24 plist-1.0.0

drwxr-xr-x    4 root  admin  136 Jul 14 11:04 plist-2.0.0

drwxr-xr-x   12 root  admin  408 Mar  8 16:03 rake-0.7.0

drwxr-xr-x    5 root  admin  170 Mar 23 20:51 rubyful_soup-1.0.4

drwxr-xr-x   20 root  admin  680 Mar  8 09:08 rubygems-update-0.8.11

drwxr-xr-x   20 root  admin  680 Jul 14 08:32 rubygems-update-0.9.0

drwxr-xr-x    3 root  admin  102 Mar  7 21:48 sources-0.0.1

drwxr-xr-x   10 root  admin  340 Mar  8 08:49 tidy-1.1.2

???

quite confusing ;-)