Problem with multicast in 6.2.0

Hello,
Could anybody help me with this.My QNX machine has RealTek
ethernet card and driver installed.(The version is Qnx Neutrino 6.2.0).
The QNX document says that multicast packets can be received by default.
But iam not able to recieve multicast packets.We are able to receive other
packets.

An explicit devctl() for setting multicast on the interface returns
failure.

In Qnx Version 6.1.0 we were able to receive multicast packets by
default.Can anybody help me

regards,
deepak