Wow, we had totally forgotten about WebUserPrefs. My boss found that ages ago and played with it and then got busy and forgot all about it. He found it on one of our old servers just now. Your post jogged his old feeble memory...
When you went through the 'config.php' file:
1. Did you setup an auth module? If so, then you can have it do per user settings, else it will be per domain settings.
2. The 'user_prefs' file for spamassassin is not automatically created by installing SA, probably why it can't find the file. Or else the $user_prefs variable path is not set properly (also depends on 1 above).
For spamassassin to be able to check a user's email, there needs to be a pipe command in the user's hidden
.qmail file which is located at:
/var/qmail/mailnames/domain.com/username/.qmail
Example: (may not be exactly the same as yours)
#cat /var/qmail/mailnames/example.com/user1/.qmail
| /usr/bin/odeiavir
| true
| /usr/bin/spamc -f -U /tmp/spamd_full.sock | /usr/bin/maildir ./Maildir/
The first line sends the mail to the anti-virus scanner, then if it passes 'true', gets piped to the spamassassin module. SA then runs it's rules and gives the email a 'score'. If the score is higher than 5 (per your post), then the subject line is appended with "*****SPAM*****" and the email is then passed to the user's Maildir
Spamassassin itself by default only tags spam, does not delete it. If you install qmail-scanner (from ART), which will coordinate and control additional things like multiple anti-virus scanners, you can configure qmail-scanner to drop emails over a certain score, but only tag those below a given score.
Never found a separate log file for SA itself, but qmail-scanner has lots of logging going on, including offending IP addresses. We love that package.
Hope I got all the highlights, don't want to be too wordy.