ruTorrent issue [Error pluguin]

So I was moving some things around to get a script working and accidentaly broke everything.
After using this line:
cp /usr/local/bin/mktorrent /usr/bin/mktorrent

My rutorrent stopped working [Bad response from server: (500 [error,getplugins]) Internal Server Error]
and I can’t seem to find my way back. I have almos 1,000 torrents running (rtorrent is still up) and I’d love not to lose them.

Any ideas?

got something like this:

[:error] [pid 1049] PHP Fatal error: Uncaught Error: Call to undefined function mb_strlen() in /srv/rutorrent/plugins/_task/task.php:142\nStack trace:\n#0 /srv/rutorrent/plugins/_task/task.php(155): rTask::tail(’/srv/rutorrent/…’)\n#1 /srv/rutorrent/plugins/_task/task.php(210): rTask::processLog(’/srv/rutorrent/…’, ‘log’, Array, 0, 18 0)\n#2 /srv/rutorrent/plugins/_task/task.php(280): rTask::check(‘1480204156583a1…’)\n#3 /srv/rutorrent/plugins/_task/task.php(301): rTaskManager::obtain()\n#4 /srv/rutorrent/plugins/_task/init.php(5): rTaskManager::cleanup()\n#5 /srv/rutorrent/php/getplugins.php(495): require_once(’/srv/rutorrent/…’)\n#6 {main}\n thrown in /srv/rutorrent/plugins/_task/task.php on line 142, referer

I found a suggestion to install this mbstring extention
but now the server is EXTREMELY slow and it keeps refreshing rutorrent but never really opens it.