steht in Post #5
bei Mac OSX hier: /etc/hosts bzw. /private/etc/hosts
bei Win7 hier: C:\Windows\system32\drivers\etc\hosts
Dateiname "hosts" (ohne Endung).
Sieht dann in etwa so aus:
# Copyright
1993-2009 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
# ::1 localhost
74.208.10.249 gs.apple.com <----------------------- löschen!
#127.0.0.1 gs.apple.com <----------------------- löschen!
Diese bearbeiten (mit NotePad z.B.) und alles wie das hier löschen
74.208.10.249 gs.apple.com
#127.0.0.1 gs.apple.com
dann die Datei speichern, iTunes neu starten und erneut versuchen - müsste klappen.