Cannot connect to Apple file servers after upgrading to 10.8
It seems that obsolete iDisk settings in OSX 10.8 may prevent you to connect to a file server.

You need to run those commands in Terminal 


defaults delete -g iToolsMember
defaults delete -g iToolsMemberDomain


to get rid of those settings.

Source: http://derflounder.wordpress.com/2012/08/03/odd-afp-and-smb-connection-problem-caused-by-idisk-going-away/