debugging CGI script for apache -- how?

[R. Luoma]

I am having problems figuring out how to debug
a failing script running as under cgi with
the apache web server.

The script runs just find by itself.

However, one of the programs called by the script
gets the rather frustrating
  Segmentation fault

What is different about the apache cgi environment?

Would any tools be useful?

Thanks.
-- 
R. Luoma