hi,
thanks for ur reply. actually, the problem is solved by configuring the NIC, its like this:

It is relatively simple to configure what interface multicast packets are to be sent out on. What is needed is a default route for multicast traffic specifying the interface.
To do this enter the following command in a terminal:


route add -net 224.0.0.0 netmask 240.0.0.0 dev eth0


The above command will route all multicast traffic out through interface eth0. To confirm the route took effect and was added to your routing table run route -n.

for more information, pls goto:
http://www.tldp.org/HOWTO/Multicast-HOWTO.html

bye
swamy