Problem with Postfix + Maildrop + MaildirQuota

Hi,

I have strange problems with maildrop with maildir quota.
Without quota everything works fine, maildrop delivers emails in just
few seconds (filtering with spamassassin, clamd and autoresponder)

Jan 10 17:21:27 XXXXX postfix/pipe[11248]: 123262408887:
to=<XXXXXXXX>, relay=virtual, delay=7.7, delays=4.9/0/0/2.9,
dsn=2.0.0, status=sent (delivered via virtual service)

3 seconds...

problem occure when I recompiled maildrop to use maildirquota.

Jan 9 14:47:08 XXXX postfix/pipe[2028]: B07862408723: to=<XXXXXX>,
relay=virtual, delay=301, delays=0.6/0.07/0/300, dsn=4.3.0,
status=deferred (tempo
rary failure. Command output: maildrop: Timeout quota exceeded. )

As you can see - email processing is still at same level, but delivery
is about 300 seconds, which causes Timeout quota exception... This
leads to uncontrolled mail queue grow and mail server to stuck.

I've tried to test delivery from command line:

#time cat mail.txt | maildrop.quota -w 90 -V1 -d XXXXXX
maildrop: Filtering through `test -d "$MAILDIR"`
maildrop: Filtering through xfilter /usr/bin/spamc -f -u spamd -d
192.168.2.3
maildrop: Filtering through xfilter formail -f -A 'Delivered-To:
XXXXX'
maildrop: Filtering through `/home/services/yaa/bin/yaa.pl`
maildrop: Filtering through `echo "*">>/tmp/mail_ok`
maildrop: maildir over quota.

real 0m2.528s
user 0m0.680s
sys 0m1.804s


- under 3 seconds... I don't understand what can be the problem...
maybe some limitations of process count of courier-authd? any help
will be appreciated...

env:
fedora 6
postfix-2.3.3-2
courier-authlib-0.59.1-1.fc6 (with mysql support for virtual
mailboxes)
maildrop-2.0.4
courier-imap-4.1.2-1.6

M