The machines may not be on the same subnet anymore, like in the thread I just responded to. I do not offhand know what error -50 means. To have your Mac connect to a server automatically, first select the server's icon and choose Make Alias from the File menu. Then open System Preferences, click on Accounts, and then click on the Startup Items button (which really should be named Login Items, but whatever. . .). Finally, drag and drop the alias you made on to list field.