[vchkpw] SMTP AUTH with vchkpw

[signo]

hello, i've problems with smtp-auth, when i try to send email from a 
client the server ask always for a password (but the passwd is ok)

please help me!!

thanks

signo

situation:

qmail: qmail-1.03
vpopmail: 5.3.28
smtp-auth patch on qmail:  qmail-smtpd-auth-0.4.2 
(http://www.fehcom.de/qmail/auth/qmail-smtpd-auth-042_tgz.bin)

qmail-smtpd/run:

#!/bin/sh
QMAILDUID=`id -u qmaild`
NOFILESGID=`id -g qmaild`
MAXSMTPD=`head -1 /var/qmail/control/concurrencyincoming`
if [ -z "$QMAILDUID" -o -z "$NOFILESGID" -o -z "$MAXSMTPD" ]; then
   echo QMAILDUID, NOFILESGID or MAXSMTPD is unset in
   echo /var/qmail/supervise/qmail-smtpd/run
   exit 1
fi
exec /usr/local/bin/softlimit -m 20000000 \
 /usr/local/bin/tcpserver -v -R  -u $QMAILDUID -x /etc/tcp.smtp.cdb -c 
"$MAXSMTPD" \
  -g "$NOFILESGID" 0 smtp /var/qmail/bin/qmail-smtpd  
/home/vpopmail/bin/vchkpw /bin/true 2>&1

telnet on port 25:

220 ssigno_back.local ESMTP
250-ssigno_back.local
250-PIPELINING
250-8BITMIME
250 AUTH LOGIN PLAIN CRAM-MD5