I am getting

webcount.rb:818: [BUG] Segmentation fault
ruby 1.6.8 (2002-12-24) [powerpc-darwin6.6]
Abort

from my program.  It happens after running the program for some tens of 
minutes, and the location identified varies apparently randomly.  (The 
program essentially downloads web pages in order to measure their size 
in terms of pages, links, images etc. for some work I am doing on 
devising new indicators of the 'digital economy').

I need advice on the best strategy to use to identify what is going 
wrong.  The program uses threads (obtained through the Resource Pooling 
code to be found at 
http://www.rubygarden.org/ruby?ObjectPoolingAndThreading), and 
net/http, both of which could, I suppose, complicate matters, and the 
program is about 900 lines of code, so a strategy is rather important!

Your advice would be much appreciated.

Nigel