Mumudvb and Join own multicast

[Nate]

I am trying to use mumudvb as supplied with your update Version 1.0.0.6.
All works fine apart from when I try use multicast_auto_join=1 in the config file.
Mumu then fails with "setsockopt IP_ADD_MEMBERSHIP ipv4 failed (multicast kernel?) : No such device";
Source code mumudvb2 network.c line 262
if (setsockopt (socket, IPPROTO_IP, IP_ADD_MEMBERSHIP, &blub, sizeof (blub)))
{
log_message( log_module, MSG_ERROR, "setsockopt IP_ADD_MEMBERSHIP ipv4 failed (multicast kernel?) : %s\n", strerror(errno));
set_interrupted(ERROR_NETWORK<<8);
}
I have added a route -
route add -net 224.0.0.0 netmask 224.0.0.0 eth0
And also tried
ifconfig eth0 allmulti
but no luck

Mumu multicasts out the channels I configure OK

Have I missed something else that I need to configure on the OS ?
Thanks,
Nate