well I am not really sure what your asking here to be honest.
external.php works fine Reeftalk.com
I can call that in an rss feed reader without fail
If your trying to discuss a mod your doing since our program has no files called the names your using you might want to open up a modification discussion since this kind of stuff is not covered under product support.
The files your noting are not part of our released code. I havent worked with rss2html too much so I doubt I could shed too much light on a program I havent used.