FreeBSD 9 as PPPoE BRAS(mpd 5.7) kernel panic

[Alex Ros]

Hello.
We have a problem with FreeBSD 9 stable (currently on r267070) as PPPoE 
BRAS by mpd 5.7. Server catches 1-3 kernel panics every month.
Two last core.txt's:
http://pkg.hostelnet.ru/pub/dump/core.txt.7.txt (r262224)
and
http://pkg.hostelnet.ru/pub/dump/core.txt.8.txt (r267070)
Now trying to test hint with mpd-down script from similar trhread: 
http://lists.freebsd.org/pipermail/freebsd-net/2014-June/038952.html
Hardware: HP DL360 with Intel 82571EB nic.
Average load on server: 150-300 Mbit/s and around 150 users.
FreeBSD configuration:
running on GENERIC kernel
IPFW with few rules (no dummynet, no nat)
routing via OSPF (quagga)

cat /boot/loader.conf
net.isr.maxthreads=2
net.isr.numthreads=2
net.graph.maxdata=65536
net.graph.maxalloc=65536
net.isr.defaultqlimit=4096
net.link.ifqmaxlen=10240

cat /etc/sysctl.conf
net.inet.ip.fastforwarding=1
net.inet.ip.redirect=0
kern.random.sys.harvest.ethernet=0
kern.random.sys.harvest.point_to_point=0
kern.random.sys.harvest.interrupt=0
net.inet.raw.maxdgram=16384
net.inet.raw.recvspace=16384
net.inet.ip.intr_queue_maxlen=10240
net.route.netisr_maxqlen=4096

Maybe someone can help to understand: it is a configuration error or a 
bug MPD/netgraph?