Before you can use Doctor you have to configure it by copying sample.conf 
to doctor.conf and editing the file according to the instructions in it.

You also need to download and install the IO::Capture module from the net:

http://groups.google.com/groups?selm=yr0e8.12924%24ZC3.1033373%40newsread2.prod.itd.earthlink.net

You can install it anywhere in the Perl path; I installed it in the doctor
root directory at IO/Capture.pm.

You probably also need to hack the Perl path at the top of doctor.cgi
to point to a reasonable location for Perl on your server.