Question about dir_cgi.c and PATH_INFO

I'm using the dir_cgi.c file to generate a directory listing for various
areas of my website.  However, where it should list the path information
(from the environment variable PATH_INFO), I'm getting nothing.

I have 'PathInfo On' as the default in my mathopd.conf file, and have
turned it off only for my BB and Blog systems, which don't like it. ;]

What information would be most useful to try to debug this (if, that is,
the list is still working)?

Regards,
-- 
dave [ please don't CC me ]