[Udpcast] multicast sender error on Solaris "Invalid argument"

[Ralf Lohmann]

Hello,

I have a problem with the multicast mode of udp-sender.
On Solaris 10 X86 and Solaris 10 Sparc it is the same
error. One udp-receiver works perfect (unicast), but if I
use two udp-receivers (I think then udp-sender switches
to unicast mode) the sender gives the following error
after starting the transfer with the anykey on the server:

Udp-sender 2009-10-31
Set multicast send interface: Invalid argument

and then the server stops. 

The Error is with udpcast-20091031 on Solaris 10 sparc
and also on Solaris 10 x86! I compiled it with a hack, 
because the missing strndup in Solaris. I also have 
compiled udpcast-20070602 without a hack on Solaris 
10 X86, because the news are saying it is Solaris 10 
x86 ready. But I got the same error with the invalid
argument.
The same error occurs, when i set --ttl from 1 to 2.

I think it is not a problem with the hardware or the
network, because udpcast with the same hardware , but
with Mandriva did work. It seems to be an Solaris related
issue.

Two Solaris-receivers with one Mandriva-sender did also
work. Only the sender breaks on Solaris. 

Can you please help me?

Best Regards
Ralf