UDP Broadcast Problem

[Goldman David]

I am attempting to send out a UDP Broadcast with the following script:

on mouseUp
   put "255.255.255.255:5000" into theIP
   open datagram socket to theIP
   write "xx" to socket theIP
   put the result
   close socket theIP
end mouseUp

However what I get is: "error sending datagram", Further the  
openSockets shows that 255.255.255.255:5000 is open.

My packet sniffer (MacSniffer) shows no activity - i.e. it really  
doesn't seem to be sending anything.

If I change the address to anything other than 255.255.255.255 - say  
0.255.255.255 - something happens.

Any idea why I can't send out the broadcast?

I'm using Rev 2.6.1 under OS X 10.4.4.

Thanks in advance for your help!

-- David Goldman