The McAfee Security Center's Firewall may be preventing Bonjour from starting up, thus halting the installation of iTunes.
By default, McAfee Security Center should prompt you when a new application or service requests internet access. When this dialog appears, chose the option to Grant Access to allow Bonjour to start. You must respond to this dialog within 30 seconds.
If you do not see this dialog, it may be located behind the installation window. If you are unable to locate the dialog, it is possible that this feature has been disabled. Restore your McAfee Security Center Firewall to its default settings in order to see this dialog by following these steps:
- Open McAfee Security Center.
- Click "Restore Firewall Defaults" under the "Common Tasks" menu on the left side of the window.
- In the "Restore Firewall Protection Defaults" portion of the window click "Restore Defaults"
If you are still unable to install iTunes, you may want to temporarily disable your McAfee Security Center Firewall.