How to disable startup connection to a 'dead' server?
My guess would be that there is a login item for the dead server. To Remove it access Systems preferences via:
-> System Preferences -> Users & Groups -> Choose your user -> Login items ->
Select the Dead Server and press "-" to remove it.
I solved this by going to Finder -> Go -> Connect to Server (command-K). In there was a "Favorite Server" that was the culprit. Removed it and the problem went away.