OK... so here I am, once again on the western technology frontier exploring unknown territory, with my buddies "Computer speakers" and "Base station xxxxx" and I choose to select them both to enter the unknown world of simultaneous music playing and..... "An error occurred while connecting to the remote speaker.... An unknown error occurred (-3256)".
Now I tried rebooting the base station, powering off, on, stopping iTunes, restarting, selecting the speakers in different orders.... I tried just about everything, well maybe not everything.... perhaps I should look to see if AirFoil has hijacked anything! (Actually I didn't fully install AirFoil, but I guess I'll have a go ..... but wait ... something just come over the internet radio (= google to you).....
If you get this error while using the built-in Mac OS X Firewall, perform these steps to make sure UDP is not blocked:
1. Open System Preferences.
2. Select the Sharing pane.
3. Click the Firewall tab.
4. Click the Advanced button.
5. Make sure that the option to "Block UDP Traffic" is not selected.
Problem solved.... except - the wife is now calling out "what you playing that for....." Can't win!
At least I'm still employed as the "Chief Technology Officer" - in my house!