[Dovecot] antispam plugin problem

[Eugene]

Hi people!
(Especially Johannes, probably =)

I recently switched to DSPAM + antispam plugin combination.
Mostly I am happy but there is a problem with calling dspam-exec in order to
relearn the messages.
Moving messages to spam folder does not work, giving the error message
'Failed to call dspam' to client.

I tried to add some debug output and here are the results:

This is the output of  debug("calling dspam: %s %s %s %s %s %s %s", argv[0],
argv[1], argv[2], argv[3], argv[4], argv[5], argv[6]);
(debugv(argv) does not produce any output for some reason)
Oct 26 02:37:12 qqqqq imap: antispam: calling dspam:
/usr/contrib/bin/dspam --source=error --class=spam --signature=490387db858421194018847
 --user genie (null)

This is the captured output of forked process
Oct 26 02:37:12 qsar imap: antispam: dspam returned: ^APdata stack: Out of
memory when allocating 1073741840 bytes

If I understand correctly, this message is produced by dovecot before it
should have launched dspam executable. I don't know why it needs 1GB  of
stack space for that. Changing dspam to dspamc does not help.

Interestingly enough, launching 'sendmail' in mailtrain mode works ok.

Do you have any ideas about what is wrong?

Best wishes
Eugene