Multi-cast mode warning

Hello,
I am currently in the process of try to get eCos (2.0.43)  running on our own hardware which uses an ATMEL AT91RM9200 CPU (bulit in MAC) and a DP83848 PHY. I have used the eCos build from the AT91RM9200-EK and the exisiting DP83847 driver (changing it to support the similar DP83848) as a base and I have got to the stage where the ethernet link is established. I am however getting the following warning message when initialising the network:

[eth_drv_ioctl] Warning: Driver can't set multi-cast mode

Now, if everything worked I wouldn't be worried about this, but I don't seem to be getting any IP packets out of the hardware (eCos is trying to send DHCP discovery messages but they aren't coming out to the ethernet). I suspect this may be a hardware issue but, I would like some confirm that the warning above is or isn't anything I need to look into.

My understanding of multi-cast mode is that I shouldn't need it or care but if anyone could confirm or deny this I'd be very grateful.
Best regards,
Tim Hatton
Coherent Research Ltd
UK