Plex Media Server fails to start on ReadyNAS 312

After a recent install of the latest package on my ReadyNAS 312 using the shell and installing the latest postgresql, my plex server fails to start.

It fails to start from the app-page on the admin site, and if I try to start it manually from the shell I get the following message:

root@NAS-Athena:/# systemctl start fvapp-plexmediaserver.service
root@NAS-Athena:/# systemctl enable fvapp-plexmediaserver.service
root@NAS-Athena:/# systemctl status fvapp-plexmediaserver.service● fvapp-plexmediaserver.service - Plex Media Server
   Loaded: loaded (/lib/systemd/system/fvapp-plexmediaserver.service; enabled; vendor preset: enabled)
   Active: activating (auto-restart) (Result: exit-code) since Sat 2017-10-07 14:20:52 WEST; 1s ago
  Process: 22549 ExecStart=/bin/sh -c /apps/plexmediaserver/Binaries/Plex\ Media\ Server (code=exited, status=134)
  Process: 22544 ExecStartPre=/bin/sh -c /usr/bin/test -d "/apps/plexmediaserver/temp" || /bin/mkdir -p "/apps/plexmediaserver/temp" (code=exited, status=0/SUCCESS)
  Process: 22540 ExecStartPre=/bin/sh -c /usr/bin/test -d "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}" || /bin/mkdir -p "${PLEX_MEDIA_SERVER_APPLICATION_SUPPORT_DIR}" (code=exited, s
tatus=0/SUCCESS)
 Main PID: 22549 (code=exited, status=134)

Oct 07 14:20:52 NAS-Athena systemd[1]: fvapp-plexmediaserver.service: Unit entered failed state.
Oct 07 14:20:52 NAS-Athena systemd[1]: fvapp-plexmediaserver.service: Failed with result 'exit-code'.

Anyone any clue how to solve this? Or even what might have caused this? I've tried uninstalling plex (both initially from the app page and rebooting and then uninstalling from the shell) - neither seems to resolve the issue.

Thanks for any help given.