SP_error: (-11) Illegal session was supplied

hi,

im trying to get spread and wackamole running to build a simple
cluster of vpnservers. the cluster should consist of two nodes
which are both online and get one out of two vips assigned.
one of the vips are told to the clients resolving vpn.dom.com.
i use simple dns roundrobin.
when one of the machines gets a problem the othermachine detects it -
shoots the machine in the head and gets the other vip assigned.

i just cant get wackamole running.

here is the output when running "wackamole -d -c /etc/wackamole.conf"

connecting to 4803
Clean_up called
Dequeued arp spoof notifier.
No such interface
Dequeued arp spoof notifier.
No such interface
Spread connect failed [-9].
Sending 3 local arp entries
SP_error: (-11) Illegal session was supplied

connecting to 4803
Clean_up called
Dequeued arp spoof notifier.
No such interface
Dequeued arp spoof notifier.
No such interface
Spread connect failed [-9].
connecting to 4803
...and-so-on



i played around with wackamole.conf,spread.conf and spread.access_ip
but nothing seems to change the behavior :(

i included those configs below. anyone got a clue what i have done wrong ?
for completeness: i use linux-2.4.21, on debian woody, wackamole-2.0.0
                  and spread-3.17.1.


thanx in advance
 gerald


-begin configs-

..i added some #comments

#[wackamole.conf]
Spread = 4803
SpreadRetryInterval = 5s
Group = my-vpn
Control = /var/run/my-vpn.it
Prefer eth0:192.168.1.98/24 #node1 real ipadress node2=192.168.1.99
VirtualInterfaces {
        { eth0:192.168.1.50/24 }    #vip one
        { eth0:192.168.1.51/24 }    #vip two
}
Arp-Cache = 90s
Notify {
        eth0:192.168.1.1/24         #the router
        arp-cache
}
balance {
        AcquisitionsPerRound = all
        interval = 4s
}
mature = 5s
#[wackamole.conf]


#[spread.conf]
Spread_Segment  127.0.0.255:4803 {
        localhost       127.0.0.1
}
                                                                                                                                        
Spread_Segment  192.168.1.255:4803 {
        vpn-uno         192.168.1.98
        vpn-due         192.168.1.99
}
DebugFlags = { PRINT EXIT }
EventLogFile = /var/log/spread.log
EventTimeStamp = "[%a %d %b %Y %H:%M:%S]"
AllowedAuthMethods = "IP"
#[spread.conf]


#[spread.access_ip]
unix
local
192.168.1.0/24
#[spread.access_ip]