Moving emails tagged as spam to the Junk folder

 I am running Ubuntu 16.04. I am following this guide: https://wiki2.dovecot.org/HowTo/AntispamWithSieve. At the end when I try to compile the .sieve files, I get this error: sievec(root): Fatal: Plugin 'sieve_imapsieve' not found from directory /usr/lib/dovecot/modules/sieve.  Does anyone know about this? I have dovecot-sieve installed and I'm using Postfix and Spamassassin.

-- Mika Leppänen -- mika.leppanen@iki.fi