If I remember right, I had a fully installed Ruby on my PC and took the REXML lib from it. The directory contains 55 files and five folders. I loaded it this way from my script:
require 'rexml/document' unless defined? REXML
If you also want to load this way you have to make sure that the Ruby interpreter search in the right place. Put the REXML folder to Plugins or Tools folder - should work with the above code.
To make sure that your script only runs if REXML is loaded, put this condition to your codee:
if defined? REXML
# YOUR CODE HERE
else
UI.messagebox "REXML is missed, can't load plugin."
end
Sorry for my late answer - I'm moving from town to town at the moment.
azuby