Problem with package arpwatch

[Bieniu]

Hi
I have AC66U with Merlin build 378.56_2 and i have problems with arpwatch package. I have msmpt working ('echo "test" | sendmail -t root' works) but arpwatch doesn't send any emails. arpwatch is working and i have notifications in log about new deices or IP change but any emails.
My /opt/etc/init.d/S04arpwatch

#!/bin/sh

ENABLED=yes
PROCS=arpwatch
ARGS="-f /opt/etc/arpwatch/arp.dat -i br0"
PREARGS=""
DESC=$PROCS
PATH=/opt/sbin:/opt/bin:/opt/usr/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

. /opt/etc/init.d/rc.func

Any solution for that?