spamassassin not learn, zmtrainsa ignores junked mail

[lukefilewalker]

OS: Cento4.4
zimbra: Open Souce edition 4.0.4

If I junked spam mail (with ****** word in body message) the spam score not increase and go in the inbox folder.
two questions:
- by default, why email spam with "buy ****** now!" in body message is not junked?
- why spamassassin not learn the junked mail?see below zmtrainsa

[zimbra@email 200611]$ zmtrainsa
[] INFO: Total messages processed: 91
[] INFO: Total messages processed: 0
Learned from 0 message(s) (91 message(s) examined).
archive-iterator: readdir found no mail in '/tmp/ham.29044' directory
Learned from 0 message(s) (0 message(s) examined).
command: '/opt/zimbra/dspam-3.6.2/bin/dspam' --class=spam --source=corpus --user 'zimbra' --mode=teft --feature=chained,noise
/opt/zimbra/dspam/bin/dspam_corpus: 1 messages, 00:00:01 elapsed, 1.00 msgs./sec.
command: '/opt/zimbra/dspam-3.6.2/bin/dspam' --class=spam --source=corpus --user 'zimbra' --mode=teft --feature=chained,noise
/opt/zimbra/dspam/bin/dspam_corpus: 1 messages, 00:00:01 elapsed, 1.00 msgs./sec.
.
.
after 91 message
.
.
command: '/opt/zimbra/dspam-3.6.2/bin/dspam' --class=spam --source=corpus --user 'zimbra' --mode=teft --feature=chained,noise
/opt/zimbra/dspam/bin/dspam_corpus: 1 messages, 00:00:01 elapsed, 1.00 msgs./sec.
command: '/opt/zimbra/dspam-3.6.2/bin/dspam' --class=spam --source=corpus --user 'zimbra' --mode=teft --feature=chained,noise
/opt/zimbra/dspam/bin/dspam_corpus: 1 messages, 00:00:01 elapsed, 1.00 msgs./sec.

if retype zmtrainsa command I obtein the same results with 91 line command displayed.