I had problem running it from CGI.
My CGI doesn't assume the path for anything, including htmldoc.
So I had to modify the doc to set the path for htmldoc as /usr/local/bin/htmldoc. It took me few hours to figure it out from my application.
This module worked great for me. I was easily able to use it to generate a PDF file. I was also happy to see that that the documentation contained a tip to allow it work under mod_perl. Before I found this I made system calls to the 'htmldoc' binary. With this module I no longer have to bother with managing temporary files myself.