I can't install the script, throws an error.

"null en https://avhn.us/lib/exe/fetch.php?media=blog:tapas_rss:tapas-rss.gif"

I'm sorry about that. I've had uptime problems on my server, and didn't realize it would cause problems installing this script. I've posted the icon asset to the Internet Archive (https://archive.org/download/tapas-rss-icon/tapas-rss.gif) and updated the script to fetch the icon from there. Hopefully this fixes the problem for you!