'451 unable to exec qq(#4.3.0)'

Hi,
I have qmail with QMAILQUEUE, and qmail-scanner and I tried to use
qmail-qfilter.
This is what I done:
1. I downloaded qmail-qfilter-2.0.tar.gz
2. unpacked
3. compiled (I've just typed "make")
4. I've added line 2 in my /etc/tcp/smtp: (192.168.10.120 is my local IP)

127.:allow,RELAYCLIENT="",RBLSMTPD="",QMAILQUEUE="/var/qmail/bin/qmail-queue"
192.168.10.120:allow,QMAILQUEUE="/home/qmail-qfilter-2.0/qmail-qfilter
/var/qmail/bin/qmail-inject -n
192.168.10.:allow,QMAILQUEUE="/var/qmail/bin/qmail-queue"
:allow,QMAILQUEUE="/var/qmail/bin/qmail-scanner-queue.pl"

5. I rebuilded smtp.cdb
Now, when I try to send any message (I use Outlook Express 6.0), I get
response from sever:
'451 unable to exec qq(#4.3.0)'

Any idea?
Radek