I am thinking it could be a permission problem as the irssi tells you to add it to the www-data user, in the screen shots for the rtorrent/rutorrent install the users names mentioned there are ubuntu and rt. Check the permission on the plugins to see who owns them. As you can see all of mine are owned by zeus the user who runs the rtorrent and rutorrent process.
Code:
root@bullseye-raspi:~# ls -l /var/www/rutorrent/plugins/
total 160
drwxrwxrwx 4 zeus zeus 4096 Oct 16 2013 check_port
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 chunks
drwxrwxrwx 3 zeus zeus 4096 Jan 7 2017 cookies
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 cpuload
drwxrwxrwx 4 zeus zeus 4096 Oct 16 2013 create
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 data
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 datadir
drwxrwxrwx 4 zeus zeus 4096 Oct 16 2013 diskspace
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 edit
drwxrwxrwx 3 zeus zeus 4096 Jan 7 2017 erasedata
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 extratio
drwxrwxrwx 5 zeus zeus 4096 Oct 16 2013 extsearch
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 feeds
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 filedrop
drwxrwxrwx 4 zeus zeus 4096 Oct 16 2013 geoip
drwxrwxrwx 2 zeus zeus 4096 Jan 7 2017 _getdir
drwxrwxrwx 3 zeus zeus 4096 Jan 7 2017 history
drwxrwxrwx 2 zeus zeus 4096 Oct 16 2013 httprpc
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 lookat
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 mediainfo
drwxrwxrwx 2 zeus zeus 4096 Oct 16 2013 _noty
drwxrwxrwx 2 zeus zeus 4096 Jun 15 2017 _noty2
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 ratio
drwxrwxrwx 3 zeus zeus 4096 Jun 15 2017 retrackers
drwxrwxrwx 2 zeus zeus 4096 Oct 16 2013 rpc
drwxrwxrwx 4 zeus zeus 4096 Oct 16 2013 rss
drwxrwxrwx 4 zeus zeus 4096 Oct 16 2013 rssurlrewrite
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 scheduler
drwxrwxrwx 3 zeus zeus 4096 Jun 15 2017 screenshots
drwxrwxrwx 3 zeus zeus 4096 Jun 15 2017 seedingtime
drwxrwxrwx 2 zeus zeus 4096 Oct 16 2013 show_peers_like_wtorrent
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 source
drwxrwxrwx 4 zeus zeus 4096 Jan 7 2017 _task
drwxrwxrwx 4 zeus zeus 4096 Jun 15 2017 theme
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 throttle
drwxrwxrwx 4 zeus zeus 4096 Oct 16 2013 tracklabels
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 trafic
drwxrwxrwx 3 zeus zeus 4096 Oct 16 2013 unpack
drwxrwxrwx 3 zeus zeus 4096 Jun 15 2017 uploadeta
drwxrwxrwx 4 zeus zeus 4096 Jun 15 2017 xmpp
You could add the user to the www-data group to have access to it I think though I am not a member of any others but my own.
Code:
zeus@bullseye-raspi:~$ groups
zeus