symsched events not executing

I’m trying to set up NAV Mac 11.0.1 to automatically do product updates/virus def updates silently in the background while non-admin users are logged-in (Mac OS X 10.5.x).
 
Using the symsched utility as outlined in this support page, I run the following (as root):
 
symsched LiveUpdate “Full Product Update” 1 1 -d 11:18 “All Products”
 
According to the man page, that should create the scheduled event and run a full product update. I confirm that the event is scheduled by running symsched -l:
 
bash-3.2# symsched -l
Module         Name                     On  UI  Freq     Day   Time   Args
-------------- ------------------------ — — -------- ----- ------ ----
LiveUpdate     Full Product Update       1   1   Daily          11:18  “All Products”
 
 
However, nothing happens except the following (from /var/log/system.log):
 
May 28 11:18:00 hostname -u[21332]: about to call FNNotifyByPath
May 28 11:18:00 hostname -u[21332]: /private/var/root/Library/Preferences/com.symantec.symsched
 
And that’s it. No actual updates get executed. (hostname removed from log details above)
 
I checked and saw that I do get this error in system.log:
 
May 28 11:16:35 hostname com.apple.launchd[1] (com.symantec.Sched0-6.plist): Unknown key: SchedName
 
How is SchedName an unknown key? I checked the plist and the SchedName key is indeed properly filled out (in this case, “Full Product Update”).
 
If I manually update through the GUI (as either non-admin with authentication by admin, or login as admin and run), then all works just fine.
 
How do I get product and virus def updates to run without non-admin end-user interaction?
 
Last details: I have tried this with the UI flag as both 1 and 0, and with and without the -quiet argument.