Error when running imapsync.pl

[markdewet]

Hi,
I'm very new to linux so please bear with me. I have an Ubuntu server 18.04 server with iRedMail installed which includes Roundcube. I installed rcimapsync exactly as per your instructions in the readme, and all seemed to install correctly as I received no errors. However I then set it up to fetch mail from a remote server as follows:
https://user-images.githubusercontent.com/44492920/47552515-2eeabe00-d905-11e8-8744-2926929903cd.png
and also added the line in the readme to my crontab but nothing happens at all. Things I did and noted:
1: there is no imapsync.pl in /var/mail as per the crontab line, so I copied the imapsync.pl file into that folder.
2: I tried running the imapsync.pl manually with perl and I get the error "cant lock /var/run/imapsync/imapsync-all.lock at /var/mail/imapsync.pl line 79"
3: I then tried to run imapsync.pl directly from the /plugins/imapsync/bin folder and got the same result as above, namely "cant lock /var/run/imapsync/imapsync-all.lock at /opt/www/roundcubemail-1.3.6/plugins/imapsync/bin/imapsync.pl line 79
I have also noted that there is no /var/run/imapsync/ folder present.
Please can you assist to get this plugin working?
Thanking you,
Mark