If you have dynamic quarantine enabled then you might see that error. I am not familiar with that error but im wondering if its because you did not have a connection to our TS servers.
As far as determining if the user should have recieved notifications, you should be able to grep out their email address in the eusrquarantine log and look for a line that begins with NOTIFY. That should tell you if the ironmail attempted to send out a notification for that user. Also make sure that they qualify for notifications, make sure they are in the correct group(s), the correct quarantine queues, esp score, etc..
Thanks for the helpful answer.
This is the actually what to 'grep' for in the CLI:
show log eusrquarantine | grep EUQR_notify
EUQR_notify:0:01092012 15:01:28:Message Details ID||FILENAME||FROMADDR||TOADDR|VIPID <msgid:filename:fromaddr:toaddr:vip> - <11313538:/ct/data/mss/00/01/13/13/538::['firstname.lastname@example.org']:0>
EUQR_notify:0:01092012 15:01:28:Created new Message ID and File <msgid:file> - <11313538:/ct/data/mss/00/01/13/13/538>