Hi folks!

I had the same problem too. The solution was the following:
http://www.mail-archive.com/netdev@vger.kernel.org/msg37951.html

Also have a look at the potential multicasting recovery problem in fs_enet driver:
http://patchwork.ozlabs.org/linuxppc/patch?id=10700

Best regards,
Matvejchikov Ilya.