touda I've found a copy of the code. It's GPL 2, so anyone can work on it.
It's just a PHP wrapper for a JavaScript clock. What errors do you get if you use it with the latest DokuWiki release?
BTW, that site appears to have gone down mid-June. Maybe something happened to @ryan-chappelle ?
I don't know much about JavaScript, but I can at least help with a working link for the current code:
https://github.com/respencer/dokuwiki-plugin-clock