Problems with Sophos Ubuntu server installation.

I've had good luck deploying to my Windows machines via Sophos Central. But I've got problems with the Ubuntu installation.
I recently uninstalled and just completed a fresh installation. 

OS: 
Distributor ID: Ubuntu
Description: Ubuntu 14.04.3 LTS
Release: 14.04
Codename: trusty

It has one Static IP and one local fixed IP, if that makes a difference.

Note: When I first ran SophosInstall.sh the installation failed because this version of Ubuntu doesn't have an /opt directory. When I created it, it installed just fine.

root@jam:# savdstatus
Sophos Anti-Virus is active and on-access scanning is running

The server registered with the Cloud just fine, but I can't trigger updates from Central, and the machine never reports updates it receives.

The first thing wrong, sav-rms kept stopping and restarting, filling my syslog:

Mar 7 16:16:01 jam kernel: init: sav-rms main process (24630) terminated with status 1
Mar 7 16:16:01 jam kernel: init: sav-rms main process ended, respawning
Mar 7 16:16:03 jam kernel: init: sav-rms main process (24648) terminated with status 1
Mar 7 16:16:03 jam kernel: init: sav-rms main process ended, respawning

I stopped sav-rms via /etc/init.d/sav-rms stop.

Started looking into the installation logs, and came across this:

root@jam:# cat sav-rms.log
Thu Mar 9 12:55:47 CST 2017
Thu Mar 9 12:55:48 CST 2017
Traceback (most recent call last):
File "savdctl.py", line 1311, in <module>
File "savdctl.py", line 1308, in command
File "savdctl.py", line 1295, in command
File "savdctl.py", line 84, in p
IOError: zipimport: can not open file /opt/sophos-av/engine/util.zip

I checked the rights for util.zip, which look okay.
-rw-r--r-- 1 root root 41127 Mar 9 12:53 util.zip

So something's busted with the sav-rms service. 
Any guesses?