Socket problem, Errno::EINVAL. Can someone explain?

Hi,
I am having trouble with sockets on my development machine (windows &
cygwin). I've done a quick test on a linux box and it doesn't seem to
show the same behaviour, i.e. it works.
Can someone explain why the following error is thrown on windows and not
on linux and if there is a workaround to fix it.

--environment.rb----
##define a socket. I am defining it in environment.rb because I am
going to use the socket in some of the models & also a script (running
via script/runner)
begin
    $socket = UDPSocket.open
    $socket.bind("",1680)
rescue Errno::EADDRINUSE
    puts "Error: #{$!}"
end

Open two consoles:
----Console 1-----
$ ./script/console
Loading development environment (Rails 2.0.2)

$socket

=> #<UDPSocket:0x2b5c71558e80>

----Console 2-----
$ ./script/console
Loading development environment (Rails 2.0.2)
Error: Address already in use - bind(2)

$socket

=> #<UDPSocket:0x2b5c71558e80>

$socket.recvfrom(512)

Errno::EINVAL: Invalid argument - recvfrom(2)
        from (irb):1:in `recvfrom'
        from (irb):1

Why can the second console see the socket but throw an error when I try
and use it. Linux doesn't seem to do this, i.e. I can use the socket in
either window.

Hi,
I am having trouble with sockets on my development machine (windows &
cygwin). I've done a quick test on a linux box and it doesn't seem
to
show the same behaviour, i.e. it works.
Can someone explain why the following error is thrown on windows and
not
on linux and if there is a workaround to fix it.

--environment.rb----
##define a socket. I am defining it in environment.rb because I am
going to use the socket in some of the models & also a script (running
via script/runner)
begin
   $socket = UDPSocket.open
   $socket.bind("",1680)
rescue Errno::EADDRINUSE
   puts "Error: #{$!}"
end

Open two consoles:
----Console 1-----
$ ./script/console
Loading development environment (Rails 2.0.2)

$socket

=> #<UDPSocket:0x2b5c71558e80>

----Console 2-----
$ ./script/console
Loading development environment (Rails 2.0.2)
Error: Address already in use - bind(2)

$socket

=> #<UDPSocket:0x2b5c71558e80>

$socket.recvfrom(512)

Errno::EINVAL: Invalid argument - recvfrom(2)
       from (irb):1:in `recvfrom'
       from (irb):1

The exception occurs when you bind the socket, not when you create it,
so $socket exists in both cases, it's just not bound in the second
console.

Fred