The 2 accounts for spam and ham learning which are created upon installation are missing in mine. I think I might have erased them, not knowing their purpose.
Of course, I get the following in the spamtrain.log -

Learned from 0 message(s) (0 message(s) examined).
bayes: synced databases from journal in 0 seconds: 1017 unique entries (2387 total entries)
[] ERROR: can not find account spam@..ServerName
[] ERROR: can not find account nonspam@..ServerName
I can still run zmtrainsa manually, but I would like my users to be able to train SA on their own. Is it possible to recreate the spam and ham accounts somehow ? I haven't been able to find this out..

Many thanks and praises to everyone involved with Zimbra - v4 has taken it to a whole new level
Thanks again,
Nir Gilboa